Implement Raster Backend on Android Viewer App

platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerActivity.java

Index: platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerActivity.java
diff --git a/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerActivity.java b/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerActivity.java
index ce5bb0dedadae99c950d0a6f01e4b9dc32a9e78f..0291f5e29145bcfd76d5f7c58ce0819763c8b2ea 100644
--- a/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerActivity.java
+++ b/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerActivity.java
@@ -32,7 +32,6 @@ public class ViewerActivity
     private ListView mDrawerList;
     private StateAdapter mStateAdapter;
 
-    private SurfaceView mView;
     private ViewerApplication mApplication;
 
     private native void onSurfaceCreated(long handle, Surface surface);
@@ -74,10 +73,9 @@ public class ViewerActivity
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
 
-        mView = (SurfaceView) findViewById(R.id.surfaceView);
-        mView.getHolder().addCallback(this);
-
-        mView.setOnTouchListener(this);
+        SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
+        surfaceView.getHolder().addCallback(this);
+        surfaceView.setOnTouchListener(this);
 
         mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
         mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,