[Remoting Android] Fix Painting After Rotation Bug

Previous CL 2132883002 removed the attachRedrawCallback() call in
Desktop.onStart() since it will be called in DesktopView.surfaceChanged().
This introduces a bug that if requestRepaint() is called before
surfaceChanged(), then mRepaintPending will be set to true and
mDisplay.redrawGraphics() will do nothing. paint() will not be called since
the redraw callback is not set, and mRepaintPending will not be set back to
false, making it skip all future render requests until paint() is triggered
by JniVideoRenderer in C++.

This CL fixes this problem by moving attachRedrawCallback() to the ctor
of DesktopView. paint() already has checks to prevent rendering happens if
the DesktopView is not ready yet.

BUG=627191

Review-Url: https://codereview.chromium.org/2136233002
Cr-Commit-Position: refs/heads/master@{#404732}

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

@@ -87,6 +87,8 @@ public DesktopView(Context context, Display display) {
         mRepaintPending = false;
 
         getHolder().addCallback(this);
+
+        attachRedrawCallback();
     }
 
     @Override
@@ -140,6 +142,9 @@ public void paint() {
         }
 
         Bitmap image = mDisplay.getVideoFrame();
+        synchronized (mRenderData) {
+            mRepaintPending = false;
+        }
         if (image == null) {
             // This can happen if the client is connected, but a complete video frame has not yet
             // been decoded.
@@ -167,7 +172,6 @@ public void paint() {
         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
@@ -240,7 +244,6 @@ public void surfaceChanged(SurfaceHolder holder, int format, int width, int heig
             mRenderData.screenHeight = height;
         }
 
-        attachRedrawCallback();
         mOnClientSizeChanged.raise(new SizeChangedEventParameter(width, height));
         requestRepaint();
     }