Renaming Remoting Android Touch Input classes to prepare for refactor.

The TrackingInputHandler class is going to be refactored in a future CL
however it is going to be split into three chunks (local input handler,
remote input handler, desk image manipulation) which confuses git to the
point that git thinks it is a new file after the rename.  This CL
updates the class/interface file and name so that history will be
preserved correctly when I split up the TrackingInputHandler class.

BUG=454549

Review URL: https://codereview.chromium.org/1437903002

Cr-Commit-Position: refs/heads/master@{#359118}

remoting/android/java/src/org/chromium/chromoting/DesktopView.java

@@ -38,7 +38,7 @@ public class DesktopView extends SurfaceView implements DesktopViewInterface,
     private static final String TAG = "Chromoting";
 
     private final RenderData mRenderData;
-    private TouchInputHandler mInputHandler;
+    private TouchInputHandlerInterface mInputHandler;
 
     /** The parent Desktop activity. */
     private Desktop mDesktop;
@@ -130,7 +130,7 @@ public DesktopView(Context context, AttributeSet attributes) {
         setFocusableInTouchMode(true);
 
         mRenderData = new RenderData();
-        mInputHandler = new TrackingInputHandler(this, context, mRenderData);
+        mInputHandler = new TouchInputHandler(this, context, mRenderData);
         mRepaintPending = false;
 
         getHolder().addCallback(this);