[Remoting Android] Fix Painting After Rotation Bug

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

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chromoting;
 
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Color;
@@ skipping 69 matching lines @@
 
         // Give this view keyboard focus, allowing us to customize the soft keyboard's settings.
         setFocusableInTouchMode(true);
 
         mRenderData = new RenderData();
         mInputHandler = new TouchInputHandler(this, context, mRenderData);
 
         mRepaintPending = false;
 
         getHolder().addCallback(this);
+
+        attachRedrawCallback();
     }
 
     @Override
     public void init(Desktop desktop, Client client) {
         Preconditions.isNull(mDesktop);
         Preconditions.isNull(mClient);
         Preconditions.notNull(desktop);
         Preconditions.notNull(client);
         mDesktop = desktop;
         mClient = client;
@@ skipping 33 matching lines @@
      * graphics thread using a JNI.
      */
     public void paint() {
         long startTimeMs = SystemClock.uptimeMillis();
 
         if (Looper.myLooper() == Looper.getMainLooper()) {
             Log.w(TAG, "Canvas being redrawn on UI thread");
         }
 
         Bitmap image = mDisplay.getVideoFrame();
+        synchronized (mRenderData) {
+            mRepaintPending = false;

[Yuwei, 2016/07/11 20:21:42]

mRepaintPending would also be frozen if image == null (we haven't seen any
problem so far?). Moving `mRepaintPending = false` above it should fix this
problem.

+        }
         if (image == null) {
             // This can happen if the client is connected, but a complete video frame has not yet
             // been decoded.
             return;
         }
 
         int width = image.getWidth();
         int height = image.getHeight();
         boolean sizeChanged = false;
         synchronized (mRenderData) {
             if (mRenderData.imageWidth != width || mRenderData.imageHeight != height) {
                 // TODO(lambroslambrou): Move this code into a sizeChanged() callback, to be
                 // triggered from native code (on the display thread) when the remote screen size
                 // changes.
                 mRenderData.imageWidth = width;
                 mRenderData.imageHeight = height;
                 sizeChanged = true;
             }
         }
         if (sizeChanged) {
             mOnHostSizeChanged.raise(new SizeChangedEventParameter(width, height));
         }
 
         Canvas canvas;
         Point cursorPosition;
         boolean drawCursor;
         synchronized (mRenderData) {
-            mRepaintPending = false;
             // Don't try to lock the canvas before it is ready, as the implementation of
             // lockCanvas() may throttle these calls to a slow rate in order to avoid consuming CPU.
             // Note that a successful call to lockCanvas() will prevent the framework from
             // destroying the Surface until it is unlocked.
             if (!mSurfaceCreated) {
                 return;
             }
             canvas = getHolder().lockCanvas();
             if (canvas == null) {
                 return;
@@ skipping 52 matching lines @@
      * Called after the canvas is initially created, then after every subsequent resize, as when
      * the display is rotated.
      */
     @Override
     public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
         synchronized (mRenderData) {
             mRenderData.screenWidth = width;
             mRenderData.screenHeight = height;
         }
 
-        attachRedrawCallback();
         mOnClientSizeChanged.raise(new SizeChangedEventParameter(width, height));
         requestRepaint();
     }
 
     public void attachRedrawCallback() {
         mDisplay.provideRedrawCallback(new Runnable() {
             @Override
             public void run() {
                 paint();
             }
@@ skipping 85 matching lines @@
     @Override
     public void setAnimationEnabled(boolean enabled) {
         synchronized (mAnimationLock) {
             if (enabled && !mInputAnimationRunning) {
                 requestRepaint();
             }
             mInputAnimationRunning = enabled;
         }
     }
 }