diff --git a/java/AndroidManifest.xml b/java/AndroidManifest.xml
index 88e867f..97f2d89 100644
--- a/java/AndroidManifest.xml
+++ b/java/AndroidManifest.xml
@@ -133,13 +133,6 @@
             </intent-filter>
         </receiver>
 
-        <receiver android:name=".personalization.DictionaryDecayBroadcastReciever"
-            android:exported="false">
-            <intent-filter>
-                <action android:name="com.android.inputmethod.latin.personalization.DICT_DECAY" />
-            </intent-filter>
-        </receiver>
-
         <receiver android:name=".DictionaryPackInstallBroadcastReceiver" android:exported="false">
             <intent-filter>
                 <action android:name="com.android.inputmethod.dictionarypack.aosp.UNKNOWN_CLIENT" />
diff --git a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
index 064d79b..b0fb91b 100644
--- a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
@@ -259,7 +259,7 @@
     /**
      * Check whether GC is needed and run GC if required.
      */
-    protected void runGCIfRequired(final boolean mindsBlockByGC) {
+    public void runGCIfRequired(final boolean mindsBlockByGC) {
         asyncExecuteTaskWithWriteLock(new Runnable() {
             @Override
             public void run() {
diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index 9c777d1..2e0ae57 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -73,7 +73,6 @@
 import com.android.inputmethod.latin.define.DebugFlags;
 import com.android.inputmethod.latin.define.ProductionFlags;
 import com.android.inputmethod.latin.inputlogic.InputLogic;
-import com.android.inputmethod.latin.personalization.DictionaryDecayBroadcastReciever;
 import com.android.inputmethod.latin.personalization.PersonalizationHelper;
 import com.android.inputmethod.latin.settings.Settings;
 import com.android.inputmethod.latin.settings.SettingsActivity;
@@ -584,7 +583,6 @@
         dictDumpFilter.addAction(DictionaryDumpBroadcastReceiver.DICTIONARY_DUMP_INTENT_ACTION);
         registerReceiver(mDictionaryDumpBroadcastReceiver, dictDumpFilter);
 
-        DictionaryDecayBroadcastReciever.setUpIntervalAlarmForDictionaryDecaying(this);
         StatsUtils.onCreate(mSettings.getCurrent(), mRichImm);
     }
 
@@ -704,7 +702,6 @@
         unregisterReceiver(mDictionaryPackInstallReceiver);
         unregisterReceiver(mDictionaryDumpBroadcastReceiver);
         mStatsUtilsManager.onDestroy(this /* context */);
-        DictionaryDecayBroadcastReciever.cancelIntervalAlarmForDictionaryDecaying(this);
         super.onDestroy();
     }
 
diff --git a/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java b/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
deleted file mode 100644
index 78b51d9..0000000
--- a/java/src/com/android/inputmethod/latin/personalization/DecayingExpandableBinaryDictionaryBase.java
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.inputmethod.latin.personalization;
-
-import android.content.Context;
-
-import com.android.inputmethod.latin.Dictionary;
-import com.android.inputmethod.latin.ExpandableBinaryDictionary;
-import com.android.inputmethod.latin.makedict.DictionaryHeader;
-
-import java.io.File;
-import java.util.Locale;
-import java.util.Map;
-
-/**
- * This class is a base class of a dictionary that supports decaying for the personalized language
- * model.
- */
-public abstract class DecayingExpandableBinaryDictionaryBase extends ExpandableBinaryDictionary {
-    private static final boolean DBG_DUMP_ON_CLOSE = false;
-
-    /** Any pair being typed or picked */
-    public static final int FREQUENCY_FOR_TYPED = 2;
-
-    public static final int FREQUENCY_FOR_WORDS_IN_DICTS = FREQUENCY_FOR_TYPED;
-    public static final int FREQUENCY_FOR_WORDS_NOT_IN_DICTS = Dictionary.NOT_A_PROBABILITY;
-
-    protected DecayingExpandableBinaryDictionaryBase(final Context context,
-            final String dictName, final Locale locale, final String dictionaryType,
-            final File dictFile) {
-        super(context, dictName, locale, dictionaryType, dictFile);
-        if (mLocale != null && mLocale.toString().length() > 1) {
-            reloadDictionaryIfRequired();
-        }
-    }
-
-    @Override
-    public void close() {
-        if (DBG_DUMP_ON_CLOSE) {
-            dumpAllWordsForDebug();
-        }
-        // Flush pending writes.
-        asyncFlushBinaryDictionary();
-        super.close();
-    }
-
-    @Override
-    protected Map<String, String> getHeaderAttributeMap() {
-        final Map<String, String> attributeMap = super.getHeaderAttributeMap();
-        attributeMap.put(DictionaryHeader.USES_FORGETTING_CURVE_KEY,
-                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
-        attributeMap.put(DictionaryHeader.HAS_HISTORICAL_INFO_KEY,
-                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
-        return attributeMap;
-    }
-
-    @Override
-    protected void loadInitialContentsLocked() {
-        // No initial contents.
-    }
-
-    /* package */ void runGCIfRequired() {
-        runGCIfRequired(false /* mindsBlockByGC */);
-    }
-
-    @Override
-    public boolean isValidWord(final String word) {
-        // Strings out of this dictionary should not be considered existing words.
-        return false;
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/personalization/DictionaryDecayBroadcastReciever.java b/java/src/com/android/inputmethod/latin/personalization/DictionaryDecayBroadcastReciever.java
deleted file mode 100644
index 0c5e5d0..0000000
--- a/java/src/com/android/inputmethod/latin/personalization/DictionaryDecayBroadcastReciever.java
+++ /dev/null
@@ -1,89 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.inputmethod.latin.personalization;
-
-import android.app.AlarmManager;
-import android.app.PendingIntent;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-
-import java.util.concurrent.TimeUnit;
-
-/**
- * Broadcast receiver for periodically updating decaying dictionaries.
- */
-public class DictionaryDecayBroadcastReciever extends BroadcastReceiver {
-    /**
-     * The root domain for the personalization.
-     */
-    private static final String PERSONALIZATION_DOMAIN =
-            "com.android.inputmethod.latin.personalization";
-
-    /**
-     * The action of the intent to tell the time to decay dictionaries.
-     */
-    private static final String DICTIONARY_DECAY_INTENT_ACTION =
-            PERSONALIZATION_DOMAIN + ".DICT_DECAY";
-
-    /**
-     * Interval to update for decaying dictionaries.
-     */
-    static final long DICTIONARY_DECAY_INTERVAL_IN_MILLIS = TimeUnit.MINUTES.toMillis(60);
-
-    private static PendingIntent getPendingIntentForDictionaryDecay(final Context context) {
-        final Intent updateIntent = new Intent(DICTIONARY_DECAY_INTENT_ACTION);
-        updateIntent.setClass(context, DictionaryDecayBroadcastReciever.class);
-        return PendingIntent.getBroadcast(context, 0 /* requestCode */,
-                updateIntent, PendingIntent.FLAG_CANCEL_CURRENT);
-    }
-
-    /**
-     * Set up interval alarm for dynamic dictionaries.
-     */
-    public static void setUpIntervalAlarmForDictionaryDecaying(final Context context) {
-        final AlarmManager alarmManager =
-                (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
-        if (null == alarmManager) {
-            return;
-        }
-        final long alarmTriggerTimeInMillis =
-                System.currentTimeMillis() + DICTIONARY_DECAY_INTERVAL_IN_MILLIS;
-        alarmManager.setInexactRepeating(AlarmManager.RTC, alarmTriggerTimeInMillis,
-                DICTIONARY_DECAY_INTERVAL_IN_MILLIS, getPendingIntentForDictionaryDecay(context));
-    }
-
-    /**
-     * Cancel interval alarm that has been set up.
-     */
-    public static void cancelIntervalAlarmForDictionaryDecaying(final Context context) {
-        final AlarmManager alarmManager =
-                (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
-        if (null == alarmManager) {
-            return;
-        }
-        alarmManager.cancel(getPendingIntentForDictionaryDecay(context));
-    }
-
-    @Override
-    public void onReceive(final Context context, final Intent intent) {
-        final String action = intent.getAction();
-        if (action.equals(DICTIONARY_DECAY_INTENT_ACTION)) {
-            PersonalizationHelper.runGCOnAllOpenedUserHistoryDictionaries();
-        }
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java b/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java
index 1c1cb4f..298e46c 100644
--- a/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java
+++ b/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java
@@ -26,7 +26,6 @@
 import java.lang.ref.SoftReference;
 import java.util.Locale;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.TimeUnit;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -68,60 +67,28 @@
         }
     }
 
-    private static int sCurrentTimestampForTesting = 0;
-    public static void currentTimeChangedForTesting(final int currentTimestamp) {
-        if (TimeUnit.MILLISECONDS.toSeconds(
-                DictionaryDecayBroadcastReciever.DICTIONARY_DECAY_INTERVAL_IN_MILLIS)
-                        < currentTimestamp - sCurrentTimestampForTesting) {
-            runGCOnAllOpenedUserHistoryDictionaries();
-        }
-    }
-
-    public static void runGCOnAllOpenedUserHistoryDictionaries() {
-        runGCOnAllDictionariesIfRequired(sLangUserHistoryDictCache);
-    }
-
-    private static <T extends DecayingExpandableBinaryDictionaryBase>
-            void runGCOnAllDictionariesIfRequired(
-                    final ConcurrentHashMap<String, SoftReference<T>> dictionaryMap) {
-        for (final ConcurrentHashMap.Entry<String, SoftReference<T>> entry
-                : dictionaryMap.entrySet()) {
-            final DecayingExpandableBinaryDictionaryBase dict = entry.getValue().get();
-            if (dict != null) {
-                dict.runGCIfRequired();
-            } else {
-                dictionaryMap.remove(entry.getKey());
-            }
-        }
-    }
-
     public static void removeAllUserHistoryDictionaries(final Context context) {
-        removeAllDictionaries(context, sLangUserHistoryDictCache,
-                UserHistoryDictionary.NAME);
-    }
-
-    private static <T extends DecayingExpandableBinaryDictionaryBase> void removeAllDictionaries(
-            final Context context, final ConcurrentHashMap<String, SoftReference<T>> dictionaryMap,
-            final String dictNamePrefix) {
-        synchronized (dictionaryMap) {
-            for (final ConcurrentHashMap.Entry<String, SoftReference<T>> entry
-                    : dictionaryMap.entrySet()) {
+        synchronized (sLangUserHistoryDictCache) {
+            for (final ConcurrentHashMap.Entry<String, SoftReference<UserHistoryDictionary>> entry
+                    : sLangUserHistoryDictCache.entrySet()) {
                 if (entry.getValue() != null) {
-                    final DecayingExpandableBinaryDictionaryBase dict = entry.getValue().get();
+                    final UserHistoryDictionary dict = entry.getValue().get();
                     if (dict != null) {
                         dict.clear();
                     }
                 }
             }
-            dictionaryMap.clear();
+            sLangUserHistoryDictCache.clear();
             final File filesDir = context.getFilesDir();
             if (filesDir == null) {
                 Log.e(TAG, "context.getFilesDir() returned null.");
                 return;
             }
-            if (!FileUtils.deleteFilteredFiles(filesDir, new DictFilter(dictNamePrefix))) {
-                Log.e(TAG, "Cannot remove all existing dictionary files. filesDir: "
-                        + filesDir.getAbsolutePath() + ", dictNamePrefix: " + dictNamePrefix);
+            final boolean filesDeleted = FileUtils.deleteFilteredFiles(
+                    filesDir, new DictFilter(UserHistoryDictionary.NAME));
+            if (!filesDeleted) {
+                Log.e(TAG, "Cannot remove dictionary files. filesDir: " + filesDir.getAbsolutePath()
+                        + ", dictNamePrefix: " + UserHistoryDictionary.NAME);
             }
         }
     }
diff --git a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
index b6286b2..54ee68d 100644
--- a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
@@ -25,9 +25,11 @@
 import com.android.inputmethod.latin.NgramContext;
 import com.android.inputmethod.latin.define.DecoderSpecificConstants;
 import com.android.inputmethod.latin.define.ProductionFlags;
+import com.android.inputmethod.latin.makedict.DictionaryHeader;
 
 import java.io.File;
 import java.util.Locale;
+import java.util.Map;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -37,17 +39,16 @@
  * auto-correction cancellation or manual picks. This allows the keyboard to adapt to the
  * typist over time.
  */
-public class UserHistoryDictionary extends DecayingExpandableBinaryDictionaryBase {
+public class UserHistoryDictionary extends ExpandableBinaryDictionary {
     static final String NAME = UserHistoryDictionary.class.getSimpleName();
 
     // TODO: Make this constructor private
     UserHistoryDictionary(final Context context, final Locale locale,
             @Nullable final String account) {
-        super(context,
-                getUserHistoryDictName(NAME, locale, null /* dictFile */, account),
-                locale,
-                Dictionary.TYPE_USER_HISTORY,
-                null /* dictFile */);
+        super(context, getUserHistoryDictName(NAME, locale, null /* dictFile */, account), locale, Dictionary.TYPE_USER_HISTORY, null);
+        if (mLocale != null && mLocale.toString().length() > 1) {
+            reloadDictionaryIfRequired();
+        }
     }
 
     /**
@@ -103,4 +104,32 @@
         userHistoryDictionary.updateEntriesForWord(ngramContext, word,
                 isValid, 1 /* count */, timestamp);
     }
+
+    @Override
+    public void close() {
+        // Flush pending writes.
+        asyncFlushBinaryDictionary();
+        super.close();
+    }
+
+    @Override
+    protected Map<String, String> getHeaderAttributeMap() {
+        final Map<String, String> attributeMap = super.getHeaderAttributeMap();
+        attributeMap.put(DictionaryHeader.USES_FORGETTING_CURVE_KEY,
+                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
+        attributeMap.put(DictionaryHeader.HAS_HISTORICAL_INFO_KEY,
+                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
+        return attributeMap;
+    }
+
+    @Override
+    protected void loadInitialContentsLocked() {
+        // No initial contents.
+    }
+
+    @Override
+    public boolean isValidWord(final String word) {
+        // Strings out of this dictionary should not be considered existing words.
+        return false;
+    }
 }
diff --git a/java/src/com/android/inputmethod/latin/utils/BinaryDictionaryUtils.java b/java/src/com/android/inputmethod/latin/utils/BinaryDictionaryUtils.java
index 23ffde2..892b967 100644
--- a/java/src/com/android/inputmethod/latin/utils/BinaryDictionaryUtils.java
+++ b/java/src/com/android/inputmethod/latin/utils/BinaryDictionaryUtils.java
@@ -21,7 +21,6 @@
 import com.android.inputmethod.latin.common.StringUtils;
 import com.android.inputmethod.latin.makedict.DictionaryHeader;
 import com.android.inputmethod.latin.makedict.UnsupportedFormatException;
-import com.android.inputmethod.latin.personalization.PersonalizationHelper;
 
 import java.io.File;
 import java.io.IOException;
@@ -123,8 +122,6 @@
      */
     @UsedForTesting
     public static int setCurrentTimeForTest(final int currentTime) {
-        final int currentNativeTimestamp = setCurrentTimeForTestNative(currentTime);
-        PersonalizationHelper.currentTimeChangedForTesting(currentNativeTimestamp);
-        return currentNativeTimestamp;
+        return setCurrentTimeForTestNative(currentTime);
     }
 }
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
deleted file mode 100644
index a51558e..0000000
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
+++ /dev/null
@@ -1,818 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.inputmethod.latin;
-
-import android.test.AndroidTestCase;
-import android.test.suitebuilder.annotation.LargeTest;
-import android.util.Pair;
-
-import com.android.inputmethod.latin.NgramContext.WordInfo;
-import com.android.inputmethod.latin.common.CodePointUtils;
-import com.android.inputmethod.latin.common.FileUtils;
-import com.android.inputmethod.latin.common.LocaleUtils;
-import com.android.inputmethod.latin.makedict.BinaryDictIOUtils;
-import com.android.inputmethod.latin.makedict.DictDecoder;
-import com.android.inputmethod.latin.makedict.DictionaryHeader;
-import com.android.inputmethod.latin.makedict.FormatSpec;
-import com.android.inputmethod.latin.makedict.FusionDictionary;
-import com.android.inputmethod.latin.makedict.FusionDictionary.PtNode;
-import com.android.inputmethod.latin.makedict.UnsupportedFormatException;
-import com.android.inputmethod.latin.utils.BinaryDictionaryUtils;
-import com.android.inputmethod.latin.utils.WordInputEventForPersonalization;
-
-import java.io.File;
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Locale;
-import java.util.Random;
-import java.util.concurrent.TimeUnit;
-
-@LargeTest
-public class BinaryDictionaryDecayingTests extends AndroidTestCase {
-    private static final String TEST_DICT_FILE_EXTENSION = ".testDict";
-    private static final String TEST_LOCALE = "test";
-    private static final int DUMMY_PROBABILITY = 0;
-    private static final int[] DICT_FORMAT_VERSIONS =
-            new int[] { FormatSpec.VERSION402, FormatSpec.VERSION403, FormatSpec.VERSION4_DEV };
-    private static final String DICTIONARY_ID = "TestDecayingBinaryDictionary";
-
-    private int mCurrentTime = 0;
-
-    @Override
-    protected void setUp() throws Exception {
-        super.setUp();
-        mCurrentTime = 0;
-        mDictFilesToBeDeleted.clear();
-        setCurrentTimeForTestMode(mCurrentTime);
-    }
-
-    @Override
-    protected void tearDown() throws Exception {
-        for (final File dictFile : mDictFilesToBeDeleted) {
-            dictFile.delete();
-        }
-        mDictFilesToBeDeleted.clear();
-        stopTestModeInNativeCode();
-        super.tearDown();
-    }
-
-    private static boolean supportsCountBasedNgram(final int formatVersion) {
-        return formatVersion >= FormatSpec.VERSION403;
-    }
-
-    private static boolean supportsNgram(final int formatVersion) {
-        return formatVersion >= FormatSpec.VERSION403;
-    }
-
-    private void onInputWord(final BinaryDictionary binaryDictionary, final String word,
-            final boolean isValidWord) {
-        binaryDictionary.updateEntriesForWordWithNgramContext(NgramContext.EMPTY_PREV_WORDS_INFO,
-                word, isValidWord, 1 /* count */, mCurrentTime /* timestamp */);
-    }
-
-    private void onInputWordWithPrevWord(final BinaryDictionary binaryDictionary, final String word,
-            final boolean isValidWord, final String prevWord) {
-        binaryDictionary.updateEntriesForWordWithNgramContext(
-                new NgramContext(new WordInfo(prevWord)), word, isValidWord, 1 /* count */,
-                mCurrentTime /* timestamp */);
-    }
-
-    private void onInputWordWithPrevWords(final BinaryDictionary binaryDictionary,
-            final String word, final boolean isValidWord, final String prevWord,
-            final String prevPrevWord) {
-        binaryDictionary.updateEntriesForWordWithNgramContext(
-                new NgramContext(new WordInfo(prevWord), new WordInfo(prevPrevWord)), word,
-                isValidWord, 1 /* count */, mCurrentTime /* timestamp */);
-    }
-
-    private void onInputWordWithBeginningOfSentenceContext(
-            final BinaryDictionary binaryDictionary, final String word, final boolean isValidWord) {
-        binaryDictionary.updateEntriesForWordWithNgramContext(NgramContext.BEGINNING_OF_SENTENCE,
-                word, isValidWord, 1 /* count */, mCurrentTime /* timestamp */);
-    }
-
-    private static boolean isValidBigram(final BinaryDictionary binaryDictionary,
-            final String word0, final String word1) {
-        return binaryDictionary.isValidNgram(new NgramContext(new WordInfo(word0)), word1);
-    }
-
-    private static boolean isValidTrigram(final BinaryDictionary binaryDictionary,
-            final String word0, final String word1, final String word2) {
-        return binaryDictionary.isValidNgram(
-                new NgramContext(new WordInfo(word1), new WordInfo(word0)), word2);
-    }
-
-    private void forcePassingShortTime(final BinaryDictionary binaryDictionary) {
-        // 30 days.
-        final int timeToElapse = (int)TimeUnit.SECONDS.convert(30, TimeUnit.DAYS);
-        mCurrentTime += timeToElapse;
-        setCurrentTimeForTestMode(mCurrentTime);
-        binaryDictionary.flushWithGC();
-    }
-
-    private void forcePassingLongTime(final BinaryDictionary binaryDictionary) {
-        // 365 days.
-        final int timeToElapse = (int)TimeUnit.SECONDS.convert(365, TimeUnit.DAYS);
-        mCurrentTime += timeToElapse;
-        setCurrentTimeForTestMode(mCurrentTime);
-        binaryDictionary.flushWithGC();
-    }
-
-    private HashSet<File> mDictFilesToBeDeleted = new HashSet<>();
-
-    private File createEmptyDictionaryAndGetFile(final int formatVersion) {
-        return createEmptyDictionaryWithAttributeMapAndGetFile(formatVersion,
-                new HashMap<String, String>());
-    }
-
-    private File createEmptyDictionaryWithAttributeMapAndGetFile(final int formatVersion,
-            final HashMap<String, String> attributeMap) {
-        try {
-            final File dictFile = createEmptyVer4DictionaryAndGetFile(formatVersion,
-                    attributeMap);
-            mDictFilesToBeDeleted.add(dictFile);
-            return dictFile;
-        } catch (final IOException e) {
-            fail(e.toString());
-        }
-        return null;
-    }
-
-    private File createEmptyVer4DictionaryAndGetFile(final int formatVersion,
-            final HashMap<String, String> attributeMap)
-            throws IOException {
-        final File file = File.createTempFile(DICTIONARY_ID, TEST_DICT_FILE_EXTENSION,
-                getContext().getCacheDir());
-        FileUtils.deleteRecursively(file);
-        attributeMap.put(DictionaryHeader.DICTIONARY_ID_KEY, DICTIONARY_ID);
-        attributeMap.put(DictionaryHeader.DICTIONARY_VERSION_KEY,
-                String.valueOf(TimeUnit.MILLISECONDS.toSeconds(System.currentTimeMillis())));
-        attributeMap.put(DictionaryHeader.USES_FORGETTING_CURVE_KEY,
-                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
-        attributeMap.put(DictionaryHeader.HAS_HISTORICAL_INFO_KEY,
-                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
-        if (BinaryDictionaryUtils.createEmptyDictFile(file.getAbsolutePath(), formatVersion,
-                LocaleUtils.constructLocaleFromString(TEST_LOCALE), attributeMap)) {
-            return file;
-        }
-        throw new IOException("Empty dictionary " + file.getAbsolutePath()
-                + " cannot be created. Foramt version: " + formatVersion);
-    }
-
-    private static BinaryDictionary getBinaryDictionary(final File dictFile) {
-        return new BinaryDictionary(dictFile.getAbsolutePath(),
-                0 /* offset */, dictFile.length(), true /* useFullEditDistance */,
-                Locale.getDefault(), TEST_LOCALE, true /* isUpdatable */);
-    }
-
-    private static int setCurrentTimeForTestMode(final int currentTime) {
-        return BinaryDictionaryUtils.setCurrentTimeForTest(currentTime);
-    }
-
-    private static int stopTestModeInNativeCode() {
-        return BinaryDictionaryUtils.setCurrentTimeForTest(-1);
-    }
-
-    public void testReadDictInJavaSide() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testReadDictInJavaSide(formatVersion);
-        }
-    }
-
-    private void testReadDictInJavaSide(final int formatVersion) {
-        setCurrentTimeForTestMode(mCurrentTime);
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWord(binaryDictionary, "ab", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "aaa", true /* isValidWord */, "a");
-        binaryDictionary.flushWithGC();
-        binaryDictionary.close();
-
-        final DictDecoder dictDecoder =
-                BinaryDictIOUtils.getDictDecoder(dictFile, 0, dictFile.length());
-        try {
-            final FusionDictionary dict =
-                    dictDecoder.readDictionaryBinary(false /* deleteDictIfBroken */);
-            PtNode ptNode = FusionDictionary.findWordInTree(dict.mRootNodeArray, "a");
-            assertNotNull(ptNode);
-            assertTrue(ptNode.isTerminal());
-            assertNotNull(ptNode.getBigram("aaa"));
-            ptNode = FusionDictionary.findWordInTree(dict.mRootNodeArray, "ab");
-            assertNotNull(ptNode);
-            assertTrue(ptNode.isTerminal());
-            ptNode = FusionDictionary.findWordInTree(dict.mRootNodeArray, "aaa");
-            assertNotNull(ptNode);
-            assertTrue(ptNode.isTerminal());
-        } catch (IOException e) {
-            fail("IOException while reading dictionary: " + e);
-        } catch (UnsupportedFormatException e) {
-            fail("Unsupported format: " + e);
-        }
-    }
-
-    public void testControlCurrentTime() {
-        final int TEST_COUNT = 1000;
-        final long seed = System.currentTimeMillis();
-        final Random random = new Random(seed);
-        final int startTime = stopTestModeInNativeCode();
-        for (int i = 0; i < TEST_COUNT; i++) {
-            final int currentTime = random.nextInt(Integer.MAX_VALUE);
-            final int currentTimeInNativeCode = setCurrentTimeForTestMode(currentTime);
-            assertEquals(currentTime, currentTimeInNativeCode);
-        }
-        final int endTime = stopTestModeInNativeCode();
-        final int MAX_ALLOWED_ELAPSED_TIME = 10;
-        assertTrue(startTime <= endTime && endTime <= startTime + MAX_ALLOWED_ELAPSED_TIME);
-    }
-
-    public void testAddValidAndInvalidWords() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testAddValidAndInvalidWords(formatVersion);
-        }
-    }
-
-    private void testAddValidAndInvalidWords(final int formatVersion) {
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-
-        onInputWord(binaryDictionary, "a", false /* isValidWord */);
-        assertFalse(binaryDictionary.isValidWord("a"));
-        onInputWord(binaryDictionary, "a", false /* isValidWord */);
-        onInputWord(binaryDictionary, "a", false /* isValidWord */);
-        assertTrue(binaryDictionary.isValidWord("a"));
-
-        onInputWordWithPrevWord(binaryDictionary, "b", false /* isValidWord */, "a");
-        assertFalse(isValidBigram(binaryDictionary, "a", "b"));
-        onInputWordWithPrevWord(binaryDictionary, "b", false /* isValidWord */, "a");
-        assertTrue(binaryDictionary.isValidWord("b"));
-        assertTrue(isValidBigram(binaryDictionary, "a", "b"));
-
-        onInputWordWithPrevWord(binaryDictionary, "c", true /* isValidWord */, "a");
-        assertTrue(isValidBigram(binaryDictionary, "a", "c"));
-
-        // Add bigrams of not valid unigrams.
-        onInputWordWithPrevWord(binaryDictionary, "y", false /* isValidWord */, "x");
-        assertFalse(isValidBigram(binaryDictionary, "x", "y"));
-        onInputWordWithPrevWord(binaryDictionary, "y", true /* isValidWord */, "x");
-        assertFalse(isValidBigram(binaryDictionary, "x", "y"));
-
-        if (!supportsNgram(formatVersion)) {
-            return;
-        }
-
-        onInputWordWithPrevWords(binaryDictionary, "c", true /* isValidWord */, "b", "a");
-        assertTrue(isValidTrigram(binaryDictionary, "a", "b", "c"));
-        assertTrue(isValidBigram(binaryDictionary, "b", "c"));
-        onInputWordWithPrevWords(binaryDictionary, "d", false /* isValidWord */, "c", "b");
-        assertFalse(isValidTrigram(binaryDictionary, "b", "c", "d"));
-        assertFalse(isValidBigram(binaryDictionary, "c", "d"));
-
-        onInputWordWithPrevWords(binaryDictionary, "cd", true /* isValidWord */, "b", "a");
-        assertTrue(isValidTrigram(binaryDictionary, "a", "b", "cd"));
-    }
-
-    public void testDecayingProbability() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testDecayingProbability(formatVersion);
-        }
-    }
-
-    private void testDecayingProbability(final int formatVersion) {
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        assertTrue(binaryDictionary.isValidWord("a"));
-        forcePassingShortTime(binaryDictionary);
-        if (supportsCountBasedNgram(formatVersion)) {
-            // Count based ngram language model doesn't support decaying based on the elapsed time.
-            assertTrue(binaryDictionary.isValidWord("a"));
-        } else {
-            assertFalse(binaryDictionary.isValidWord("a"));
-        }
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(binaryDictionary.isValidWord("a"));
-
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        assertTrue(binaryDictionary.isValidWord("a"));
-        forcePassingShortTime(binaryDictionary);
-        assertTrue(binaryDictionary.isValidWord("a"));
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(binaryDictionary.isValidWord("a"));
-
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "b", true /* isValidWord */, "a");
-        assertTrue(isValidBigram(binaryDictionary, "a", "b"));
-        forcePassingShortTime(binaryDictionary);
-        if (supportsCountBasedNgram(formatVersion)) {
-            assertTrue(isValidBigram(binaryDictionary, "a", "b"));
-        } else {
-            assertFalse(isValidBigram(binaryDictionary, "a", "b"));
-        }
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(isValidBigram(binaryDictionary, "a", "b"));
-
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "b", true /* isValidWord */, "a");
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "b", true /* isValidWord */, "a");
-        onInputWord(binaryDictionary, "a", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "b", true /* isValidWord */, "a");
-        assertTrue(isValidBigram(binaryDictionary, "a", "b"));
-        forcePassingShortTime(binaryDictionary);
-        assertTrue(isValidBigram(binaryDictionary, "a", "b"));
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(isValidBigram(binaryDictionary, "a", "b"));
-
-        if (!supportsNgram(formatVersion)) {
-            return;
-        }
-
-        onInputWord(binaryDictionary, "ab", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "bc", true /* isValidWord */, "ab");
-        onInputWordWithPrevWords(binaryDictionary, "cd", true /* isValidWord */, "bc", "ab");
-        assertTrue(isValidTrigram(binaryDictionary, "ab", "bc", "cd"));
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(isValidTrigram(binaryDictionary, "ab", "bc", "cd"));
-
-        onInputWord(binaryDictionary, "ab", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "bc", true /* isValidWord */, "ab");
-        onInputWordWithPrevWords(binaryDictionary, "cd", true /* isValidWord */, "bc", "ab");
-        onInputWord(binaryDictionary, "ab", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "bc", true /* isValidWord */, "ab");
-        onInputWordWithPrevWords(binaryDictionary, "cd", true /* isValidWord */, "bc", "ab");
-        onInputWord(binaryDictionary, "ab", true /* isValidWord */);
-        onInputWordWithPrevWord(binaryDictionary, "bc", true /* isValidWord */, "ab");
-        onInputWordWithPrevWords(binaryDictionary, "cd", true /* isValidWord */, "bc", "ab");
-        forcePassingShortTime(binaryDictionary);
-        assertTrue(isValidTrigram(binaryDictionary, "ab", "bc", "cd"));
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(isValidTrigram(binaryDictionary, "ab", "bc", "cd"));
-
-        binaryDictionary.close();
-    }
-
-    public void testAddManyUnigramsToDecayingDict() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testAddManyUnigramsToDecayingDict(formatVersion);
-        }
-    }
-
-    private void testAddManyUnigramsToDecayingDict(final int formatVersion) {
-        final int unigramCount = 30000;
-        final int unigramTypedCount = 100000;
-        final int codePointSetSize = 50;
-        final long seed = System.currentTimeMillis();
-        final Random random = new Random(seed);
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-        setCurrentTimeForTestMode(mCurrentTime);
-
-        final int[] codePointSet = CodePointUtils.generateCodePointSet(codePointSetSize, random);
-        final ArrayList<String> words = new ArrayList<>();
-
-        for (int i = 0; i < unigramCount; i++) {
-            final String word = CodePointUtils.generateWord(random, codePointSet);
-            words.add(word);
-        }
-
-        final int maxUnigramCount = Integer.parseInt(
-                binaryDictionary.getPropertyForGettingStats(
-                        BinaryDictionary.MAX_UNIGRAM_COUNT_QUERY));
-        for (int i = 0; i < unigramTypedCount; i++) {
-            final String word = words.get(random.nextInt(words.size()));
-            onInputWord(binaryDictionary, word, true /* isValidWord */);
-
-            if (binaryDictionary.needsToRunGC(true /* mindsBlockByGC */)) {
-                final int unigramCountBeforeGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.UNIGRAM_COUNT_QUERY));
-                while (binaryDictionary.needsToRunGC(true /* mindsBlockByGC */)) {
-                    forcePassingShortTime(binaryDictionary);
-                }
-                final int unigramCountAfterGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.UNIGRAM_COUNT_QUERY));
-                assertTrue(unigramCountBeforeGC > unigramCountAfterGC);
-            }
-        }
-
-        assertTrue(Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                BinaryDictionary.UNIGRAM_COUNT_QUERY)) > 0);
-        assertTrue(Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                BinaryDictionary.UNIGRAM_COUNT_QUERY)) <= maxUnigramCount);
-        forcePassingLongTime(binaryDictionary);
-        assertEquals(0, Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                BinaryDictionary.UNIGRAM_COUNT_QUERY)));
-    }
-
-    public void testOverflowUnigrams() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testOverflowUnigrams(formatVersion);
-        }
-    }
-
-    private void testOverflowUnigrams(final int formatVersion) {
-        final int unigramCount = 20000;
-        final int eachUnigramTypedCount = 2;
-        final int strongUnigramTypedCount = 20;
-        final int weakUnigramTypedCount = 1;
-        final int codePointSetSize = 50;
-        final long seed = System.currentTimeMillis();
-        final Random random = new Random(seed);
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-        setCurrentTimeForTestMode(mCurrentTime);
-        final int[] codePointSet = CodePointUtils.generateCodePointSet(codePointSetSize, random);
-
-        final String strong = "strong";
-        final String weak = "weak";
-        for (int j = 0; j < strongUnigramTypedCount; j++) {
-            onInputWord(binaryDictionary, strong, true /* isValidWord */);
-        }
-        for (int j = 0; j < weakUnigramTypedCount; j++) {
-            onInputWord(binaryDictionary, weak, true /* isValidWord */);
-        }
-        assertTrue(binaryDictionary.isValidWord(strong));
-        assertTrue(binaryDictionary.isValidWord(weak));
-
-        for (int i = 0; i < unigramCount; i++) {
-            final String word = CodePointUtils.generateWord(random, codePointSet);
-            for (int j = 0; j < eachUnigramTypedCount; j++) {
-                onInputWord(binaryDictionary, word, true /* isValidWord */);
-            }
-            if (binaryDictionary.needsToRunGC(true /* mindsBlockByGC */)) {
-                final int unigramCountBeforeGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.UNIGRAM_COUNT_QUERY));
-                assertTrue(binaryDictionary.isValidWord(strong));
-                assertTrue(binaryDictionary.isValidWord(weak));
-                binaryDictionary.flushWithGC();
-                final int unigramCountAfterGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.UNIGRAM_COUNT_QUERY));
-                assertTrue(unigramCountBeforeGC > unigramCountAfterGC);
-                assertFalse(binaryDictionary.isValidWord(weak));
-                assertTrue(binaryDictionary.isValidWord(strong));
-                break;
-            }
-        }
-    }
-
-    public void testAddManyBigramsToDecayingDict() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testAddManyBigramsToDecayingDict(formatVersion);
-        }
-    }
-
-    private void testAddManyBigramsToDecayingDict(final int formatVersion) {
-        final int maxUnigramCount = 5000;
-        final int maxBigramCount = 10000;
-        final HashMap<String, String> attributeMap = new HashMap<>();
-        attributeMap.put(DictionaryHeader.MAX_UNIGRAM_COUNT_KEY, String.valueOf(maxUnigramCount));
-        attributeMap.put(DictionaryHeader.MAX_BIGRAM_COUNT_KEY, String.valueOf(maxBigramCount));
-
-        final int unigramCount = 5000;
-        final int bigramCount = 30000;
-        final int bigramTypedCount = 100000;
-        final int codePointSetSize = 50;
-        final long seed = System.currentTimeMillis();
-        final Random random = new Random(seed);
-
-        setCurrentTimeForTestMode(mCurrentTime);
-        final File dictFile = createEmptyDictionaryWithAttributeMapAndGetFile(formatVersion,
-                attributeMap);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-
-        final int[] codePointSet = CodePointUtils.generateCodePointSet(codePointSetSize, random);
-        final ArrayList<String> words = new ArrayList<>();
-        final ArrayList<Pair<String, String>> bigrams = new ArrayList<>();
-
-        for (int i = 0; i < unigramCount; ++i) {
-            final String word = CodePointUtils.generateWord(random, codePointSet);
-            words.add(word);
-        }
-        for (int i = 0; i < bigramCount; ++i) {
-            final int word0Index = random.nextInt(words.size());
-            int word1Index = random.nextInt(words.size() - 1);
-            if (word1Index >= word0Index) {
-                word1Index += 1;
-            }
-            final String word0 = words.get(word0Index);
-            final String word1 = words.get(word1Index);
-            final Pair<String, String> bigram = new Pair<>(word0, word1);
-            bigrams.add(bigram);
-        }
-
-        for (int i = 0; i < bigramTypedCount; ++i) {
-            final Pair<String, String> bigram = bigrams.get(random.nextInt(bigrams.size()));
-            onInputWord(binaryDictionary, bigram.first, true /* isValidWord */);
-            onInputWordWithPrevWord(binaryDictionary, bigram.second, true /* isValidWord */,
-                    bigram.first);
-
-            if (binaryDictionary.needsToRunGC(true /* mindsBlockByGC */)) {
-                final int bigramCountBeforeGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.BIGRAM_COUNT_QUERY));
-                while (binaryDictionary.needsToRunGC(true /* mindsBlockByGC */)) {
-                    forcePassingShortTime(binaryDictionary);
-                }
-                final int bigramCountAfterGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.BIGRAM_COUNT_QUERY));
-                assertTrue(bigramCountBeforeGC > bigramCountAfterGC);
-            }
-        }
-        forcePassingShortTime(binaryDictionary);
-        assertTrue(Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                BinaryDictionary.BIGRAM_COUNT_QUERY)) > 0);
-        assertTrue(Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                BinaryDictionary.BIGRAM_COUNT_QUERY)) <= maxBigramCount);
-        forcePassingLongTime(binaryDictionary);
-        assertEquals(0, Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                BinaryDictionary.BIGRAM_COUNT_QUERY)));
-    }
-
-    public void testOverflowBigrams() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testOverflowBigrams(formatVersion);
-        }
-    }
-
-    private void testOverflowBigrams(final int formatVersion) {
-        final int maxUnigramCount = 5000;
-        final int maxBigramCount = 10000;
-        final HashMap<String, String> attributeMap = new HashMap<>();
-        attributeMap.put(DictionaryHeader.MAX_UNIGRAM_COUNT_KEY, String.valueOf(maxUnigramCount));
-        attributeMap.put(DictionaryHeader.MAX_BIGRAM_COUNT_KEY, String.valueOf(maxBigramCount));
-
-        final int bigramCount = 20000;
-        final int unigramCount = 1000;
-        final int unigramTypedCount = 20;
-        final int eachBigramTypedCount = 2;
-        final int strongBigramTypedCount = 20;
-        final int weakBigramTypedCount = 1;
-        final int codePointSetSize = 50;
-        final long seed = System.currentTimeMillis();
-        final Random random = new Random(seed);
-        setCurrentTimeForTestMode(mCurrentTime);
-        final File dictFile = createEmptyDictionaryWithAttributeMapAndGetFile(formatVersion,
-                attributeMap);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-        final int[] codePointSet = CodePointUtils.generateCodePointSet(codePointSetSize, random);
-
-        final ArrayList<String> words = new ArrayList<>();
-        for (int i = 0; i < unigramCount; i++) {
-            final String word = CodePointUtils.generateWord(random, codePointSet);
-            words.add(word);
-            for (int j = 0; j < unigramTypedCount; j++) {
-                onInputWord(binaryDictionary, word, true /* isValidWord */);
-            }
-        }
-        final String strong = "strong";
-        final String weak = "weak";
-        final String target = "target";
-        for (int j = 0; j < unigramTypedCount; j++) {
-            onInputWord(binaryDictionary, weak, true /* isValidWord */);
-            onInputWord(binaryDictionary, strong, true /* isValidWord */);
-        }
-        binaryDictionary.flushWithGC();
-        for (int j = 0; j < strongBigramTypedCount; j++) {
-            onInputWordWithPrevWord(binaryDictionary, target, true /* isValidWord */, strong);
-        }
-        for (int j = 0; j < weakBigramTypedCount; j++) {
-            onInputWordWithPrevWord(binaryDictionary, target, true /* isValidWord */, weak);
-        }
-        assertTrue(isValidBigram(binaryDictionary, strong, target));
-        assertTrue(isValidBigram(binaryDictionary, weak, target));
-
-        for (int i = 0; i < bigramCount; i++) {
-            final int word0Index = random.nextInt(words.size());
-            final String word0 = words.get(word0Index);
-            final int index = random.nextInt(words.size() - 1);
-            final int word1Index = (index >= word0Index) ? index + 1 : index;
-            final String word1 = words.get(word1Index);
-
-            for (int j = 0; j < eachBigramTypedCount; j++) {
-                onInputWordWithPrevWord(binaryDictionary, word1, true /* isValidWord */, word0);
-            }
-            if (binaryDictionary.needsToRunGC(true /* mindsBlockByGC */)) {
-                final int bigramCountBeforeGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.BIGRAM_COUNT_QUERY));
-                binaryDictionary.flushWithGC();
-                final int bigramCountAfterGC =
-                        Integer.parseInt(binaryDictionary.getPropertyForGettingStats(
-                                BinaryDictionary.BIGRAM_COUNT_QUERY));
-                assertTrue(bigramCountBeforeGC > bigramCountAfterGC);
-                assertTrue(isValidBigram(binaryDictionary, strong, target));
-                assertFalse(isValidBigram(binaryDictionary, weak, target));
-                break;
-            }
-        }
-    }
-
-    public void testDictMigration() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, formatVersion);
-        }
-    }
-
-    private void testDictMigration(final int fromFormatVersion, final int toFormatVersion) {
-        setCurrentTimeForTestMode(mCurrentTime);
-        final File dictFile = createEmptyDictionaryAndGetFile(fromFormatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-        onInputWord(binaryDictionary, "aaa", true /* isValidWord */);
-        assertTrue(binaryDictionary.isValidWord("aaa"));
-        onInputWord(binaryDictionary, "ccc", true /* isValidWord */);
-        onInputWord(binaryDictionary, "ccc", true /* isValidWord */);
-        onInputWord(binaryDictionary, "ccc", true /* isValidWord */);
-        onInputWord(binaryDictionary, "ccc", true /* isValidWord */);
-        onInputWord(binaryDictionary, "ccc", true /* isValidWord */);
-
-        onInputWordWithPrevWord(binaryDictionary, "abc", true /* isValidWord */, "aaa");
-        assertTrue(isValidBigram(binaryDictionary, "aaa", "abc"));
-        onInputWordWithPrevWord(binaryDictionary, "bbb", false /* isValidWord */, "aaa");
-        assertFalse(binaryDictionary.isValidWord("bbb"));
-        assertFalse(isValidBigram(binaryDictionary, "aaa", "bbb"));
-
-        if (supportsNgram(toFormatVersion)) {
-            onInputWordWithPrevWords(binaryDictionary, "xyz", true, "abc", "aaa");
-            assertTrue(isValidTrigram(binaryDictionary, "aaa", "abc", "xyz"));
-            onInputWordWithPrevWords(binaryDictionary, "def", false, "abc", "aaa");
-            assertFalse(isValidTrigram(binaryDictionary, "aaa", "abc", "def"));
-        }
-
-        assertEquals(fromFormatVersion, binaryDictionary.getFormatVersion());
-        assertTrue(binaryDictionary.migrateTo(toFormatVersion));
-        assertTrue(binaryDictionary.isValidDictionary());
-        assertEquals(toFormatVersion, binaryDictionary.getFormatVersion());
-        assertTrue(binaryDictionary.isValidWord("aaa"));
-        assertFalse(binaryDictionary.isValidWord("bbb"));
-        if (supportsCountBasedNgram(toFormatVersion)) {
-            assertTrue(binaryDictionary.getFrequency("aaa") < binaryDictionary.getFrequency("ccc"));
-            onInputWord(binaryDictionary, "bbb", false /* isValidWord */);
-            assertTrue(binaryDictionary.isValidWord("bbb"));
-        }
-        assertTrue(isValidBigram(binaryDictionary, "aaa", "abc"));
-        assertFalse(isValidBigram(binaryDictionary, "aaa", "bbb"));
-        if (supportsCountBasedNgram(toFormatVersion)) {
-            onInputWordWithPrevWord(binaryDictionary, "bbb", false /* isValidWord */, "aaa");
-            assertTrue(isValidBigram(binaryDictionary, "aaa", "bbb"));
-        }
-        if (supportsNgram(toFormatVersion)) {
-            assertTrue(isValidTrigram(binaryDictionary, "aaa", "abc", "xyz"));
-            assertFalse(isValidTrigram(binaryDictionary, "aaa", "abc", "def"));
-            onInputWordWithPrevWords(binaryDictionary, "def", false, "abc", "aaa");
-            assertTrue(isValidTrigram(binaryDictionary, "aaa", "abc", "def"));
-        }
-
-        binaryDictionary.close();
-    }
-
-    public void testBeginningOfSentence() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testBeginningOfSentence(formatVersion);
-        }
-    }
-
-    private void testBeginningOfSentence(final int formatVersion) {
-        setCurrentTimeForTestMode(mCurrentTime);
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-
-        binaryDictionary.addUnigramEntry("", DUMMY_PROBABILITY,
-                true /* isBeginningOfSentence */, true /* isNotAWord */,
-                false /* isPossiblyOffensive */, mCurrentTime);
-        final NgramContext beginningOfSentenceContext = NgramContext.BEGINNING_OF_SENTENCE;
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
-        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
-        assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
-        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
-        assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
-        assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
-        forcePassingLongTime(binaryDictionary);
-        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
-        assertFalse(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "aaa", true /* isValidWord */);
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
-        onInputWordWithBeginningOfSentenceContext(binaryDictionary, "bbb", true /* isValidWord */);
-        assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "aaa"));
-        assertTrue(binaryDictionary.isValidNgram(beginningOfSentenceContext, "bbb"));
-        binaryDictionary.close();
-    }
-
-    public void testRemoveUnigrams() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testRemoveUnigrams(formatVersion);
-        }
-    }
-
-    private void testRemoveUnigrams(final int formatVersion) {
-        final int unigramInputCount = 20;
-        setCurrentTimeForTestMode(mCurrentTime);
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-
-        onInputWord(binaryDictionary, "aaa", false /* isValidWord */);
-        assertFalse(binaryDictionary.isValidWord("aaa"));
-        for (int i = 0; i < unigramInputCount; i++) {
-            onInputWord(binaryDictionary, "aaa", false /* isValidWord */);
-        }
-        assertTrue(binaryDictionary.isValidWord("aaa"));
-        assertTrue(binaryDictionary.removeUnigramEntry("aaa"));
-        assertFalse(binaryDictionary.isValidWord("aaa"));
-        onInputWord(binaryDictionary, "aaa", false /* isValidWord */);
-        assertFalse(binaryDictionary.isValidWord("aaa"));
-        onInputWord(binaryDictionary, "aaa", false /* isValidWord */);
-        assertTrue(binaryDictionary.isValidWord("aaa"));
-        assertTrue(binaryDictionary.removeUnigramEntry("aaa"));
-        assertFalse(binaryDictionary.isValidWord("aaa"));
-        binaryDictionary.close();
-    }
-
-    public void testUpdateEntriesForInputEvents() {
-        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
-            testUpdateEntriesForInputEvents(formatVersion);
-        }
-    }
-
-    private void testUpdateEntriesForInputEvents(final int formatVersion) {
-        setCurrentTimeForTestMode(mCurrentTime);
-        final int codePointSetSize = 20;
-        final int EVENT_COUNT = 1000;
-        final double CONTINUE_RATE = 0.9;
-        final long seed = System.currentTimeMillis();
-        final Random random = new Random(seed);
-        final File dictFile = createEmptyDictionaryAndGetFile(formatVersion);
-
-        final int[] codePointSet = CodePointUtils.generateCodePointSet(codePointSetSize, random);
-        final ArrayList<String> unigrams = new ArrayList<>();
-        final ArrayList<Pair<String, String>> bigrams = new ArrayList<>();
-        final ArrayList<Pair<Pair<String, String>, String>> trigrams = new ArrayList<>();
-
-        final WordInputEventForPersonalization[] inputEvents =
-                new WordInputEventForPersonalization[EVENT_COUNT];
-        NgramContext ngramContext = NgramContext.EMPTY_PREV_WORDS_INFO;
-        int prevWordCount = 0;
-        for (int i = 0; i < inputEvents.length; i++) {
-            final String word = CodePointUtils.generateWord(random, codePointSet);
-            inputEvents[i] = new WordInputEventForPersonalization(word, ngramContext, mCurrentTime);
-            unigrams.add(word);
-            if (prevWordCount >= 2) {
-                final Pair<String, String> prevWordsPair = bigrams.get(bigrams.size() - 1);
-                trigrams.add(new Pair<>(prevWordsPair, word));
-            }
-            if (prevWordCount >= 1) {
-                bigrams.add(new Pair<>(ngramContext.getNthPrevWord(1 /* n */).toString(), word));
-            }
-            if (random.nextDouble() > CONTINUE_RATE) {
-                ngramContext = NgramContext.EMPTY_PREV_WORDS_INFO;
-                prevWordCount = 0;
-            } else {
-                ngramContext = ngramContext.getNextNgramContext(new WordInfo(word));
-                prevWordCount++;
-            }
-        }
-        final BinaryDictionary binaryDictionary = getBinaryDictionary(dictFile);
-        binaryDictionary.updateEntriesForInputEvents(inputEvents);
-
-        for (final String word : unigrams) {
-            assertTrue(binaryDictionary.isInDictionary(word));
-        }
-        for (final Pair<String, String> bigram : bigrams) {
-            assertTrue(isValidBigram(binaryDictionary, bigram.first, bigram.second));
-        }
-        if (!supportsNgram(formatVersion)) {
-            return;
-        }
-        for (final Pair<Pair<String, String>, String> trigram : trigrams) {
-            assertTrue(isValidTrigram(binaryDictionary, trigram.first.first, trigram.first.second,
-                    trigram.second));
-        }
-    }
-}
diff --git a/tests/src/com/android/inputmethod/latin/personalization/UserHistoryDictionaryTests.java b/tests/src/com/android/inputmethod/latin/personalization/UserHistoryDictionaryTests.java
index e1260f6..559f286 100644
--- a/tests/src/com/android/inputmethod/latin/personalization/UserHistoryDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/personalization/UserHistoryDictionaryTests.java
@@ -21,15 +21,11 @@
 import android.util.Log;
 
 import com.android.inputmethod.latin.ExpandableBinaryDictionary;
-import com.android.inputmethod.latin.NgramContext;
-import com.android.inputmethod.latin.NgramContext.WordInfo;
 import com.android.inputmethod.latin.utils.BinaryDictionaryUtils;
 
 import java.io.File;
-import java.util.List;
 import java.util.Locale;
 import java.util.Random;
-import java.util.concurrent.TimeUnit;
 
 /**
  * Unit tests for UserHistoryDictionary
@@ -87,20 +83,6 @@
         setCurrentTimeForTestMode(mCurrentTime);
     }
 
-    private void forcePassingShortTime() {
-        // 3 days.
-        final int timeToElapse = (int)TimeUnit.DAYS.toSeconds(3);
-        mCurrentTime += timeToElapse;
-        setCurrentTimeForTestMode(mCurrentTime);
-    }
-
-    private void forcePassingLongTime() {
-        // 365 days.
-        final int timeToElapse = (int)TimeUnit.DAYS.toSeconds(365);
-        mCurrentTime += timeToElapse;
-        setCurrentTimeForTestMode(mCurrentTime);
-    }
-
     private static int setCurrentTimeForTestMode(final int currentTime) {
         return BinaryDictionaryUtils.setCurrentTimeForTest(currentTime);
     }
@@ -228,46 +210,4 @@
                 numberOfWords, random, true /* checksContents */, mCurrentTime));
         assertDictionaryExists(dict, dictFile);
     }
-
-    public void testDecaying() {
-        doTestDecaying(TEST_ACCOUNT);
-    }
-
-    public void testDecaying_NullAccount() {
-        doTestDecaying(null /* testAccount */);
-    }
-
-    private void doTestDecaying(final String testAccount) {
-        final Locale dummyLocale = UserHistoryDictionaryTestsHelper.getDummyLocale("decaying");
-        final UserHistoryDictionary dict = PersonalizationHelper.getUserHistoryDictionary(
-                getContext(), dummyLocale, testAccount);
-        resetCurrentTimeForTestMode();
-        clearHistory(dict);
-        dict.waitAllTasksForTests();
-
-        final int numberOfWords = 5000;
-        final Random random = new Random(123456);
-        final List<String> words = UserHistoryDictionaryTestsHelper.generateWords(numberOfWords,
-                random);
-        NgramContext ngramContext = NgramContext.EMPTY_PREV_WORDS_INFO;
-        for (final String word : words) {
-            UserHistoryDictionary.addToDictionary(dict, ngramContext, word, true, mCurrentTime);
-            ngramContext = ngramContext.getNextNgramContext(new WordInfo(word));
-            dict.waitAllTasksForTests();
-            assertTrue(dict.isInDictionary(word));
-        }
-        forcePassingShortTime();
-        dict.runGCIfRequired();
-        dict.waitAllTasksForTests();
-        for (final String word : words) {
-            assertTrue(dict.isInDictionary(word));
-        }
-        // Long term decay results in words removed from the dictionary.
-        forcePassingLongTime();
-        dict.runGCIfRequired();
-        dict.waitAllTasksForTests();
-        for (final String word : words) {
-            assertFalse(dict.isInDictionary(word));
-        }
-    }
 }
\ No newline at end of file