Use ArrayList constructor directly

This is a follow up of I85a0b18d2d.

Change-Id: Ia7a642bb6e0015242d6e046019b3973226a0add2
diff --git a/java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java b/java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java
index 397c098..67a2227 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java
@@ -213,8 +213,7 @@
             if (mCachedGridKeys != null) {
                 return mCachedGridKeys;
             }
-            final ArrayList<Key> cachedKeys = CollectionUtils.newArrayList(mGridKeys.size());
-            cachedKeys.addAll(mGridKeys);
+            final ArrayList<Key> cachedKeys = new ArrayList<Key>(mGridKeys);
             mCachedGridKeys = Collections.unmodifiableList(cachedKeys);
             return mCachedGridKeys;
         }