Add stub implementations for logging changes

Add abstract Logger class that serves as a contract for actual
logging implementations.

Bug: 23164804

Change-Id: Idaedae9b03aa60bbee21574584b47e3529ee9cad
diff --git a/src/com/android/dialer/logging/Logger.java b/src/com/android/dialer/logging/Logger.java
new file mode 100644
index 0000000..3007077
--- /dev/null
+++ b/src/com/android/dialer/logging/Logger.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2015 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.dialer.logging;
+
+import android.app.Activity;
+
+import com.android.dialerbind.ObjectFactory;
+import com.android.incallui.Call;
+
+public abstract class Logger {
+
+    public static Logger getInstance() {
+        return ObjectFactory.getLoggerInstance();
+    }
+
+    /**
+     * Logs a call event. PII like the call's number or caller details should never be logged.
+     *
+     * @param call to log.
+     */
+    public static void logCall(Call call) {
+        final Logger logger = getInstance();
+        if (logger != null) {
+            logger.logCallImpl(call);
+        }
+    }
+
+    /**
+     * Logs an event indicating that a screen/fragment was displayed.
+     *
+     * @param fragmentName of the displayed fragment.
+     * @param activity Parent activity of the fragment.
+     * @param tag Optional string used to provide additional information about the fragment.
+     */
+    public static void logScreenView(String fragmentName, Activity activity, String tag) {
+        final Logger logger = getInstance();
+        if (logger != null) {
+            logger.logScreenViewImpl(fragmentName, activity, tag);
+        }
+    }
+
+    public abstract void logCallImpl(Call call);
+    public abstract void logScreenViewImpl(String fragmentName, Activity activity, String tag);
+}
diff --git a/src/com/android/dialerbind/ObjectFactory.java b/src/com/android/dialerbind/ObjectFactory.java
index d67ada0..c64afe8 100644
--- a/src/com/android/dialerbind/ObjectFactory.java
+++ b/src/com/android/dialerbind/ObjectFactory.java
@@ -22,6 +22,7 @@
 
 import com.android.dialer.calllog.CallLogAdapter;
 import com.android.dialer.calllog.ContactInfoHelper;
+import com.android.dialer.logging.Logger;
 import com.android.dialer.service.CachedNumberLookupService;
 import com.android.dialer.voicemail.VoicemailPlaybackPresenter;
 
@@ -59,4 +60,9 @@
                 voicemailPlaybackPresenter,
                 isCallLogActivity);
     }
+
+    public static Logger getLoggerInstance() {
+        // no-op
+        return null;
+    }
 }