ResearchLogger invocation tests

- Start with just a smoke test.
- Sets up a private SharedPreferences

multi-project commit with I81cceba23692d64c2ea58a46351fc36d118ff825

Change-Id: I96e02d9a8de70cb5c03fd7411b886903e7a83673

java/src/com/android/inputmethod/research/ResearchLogger.java

@@ -184,7 +184,7 @@ public class ResearchLogger implements SharedPreferences.OnSharedPreferenceChang
     private Suggest mSuggest;
     private MainKeyboardView mMainKeyboardView;
     // TODO: Check whether a superclass can be used instead of LatinIME.
-    private LatinIME mLatinIME;
+    /* package for test */ LatinIME mLatinIME;
     private final Statistics mStatistics;
     private final MotionEventReader mMotionEventReader = new MotionEventReader();
     private final Replayer mReplayer = new Replayer();