Gallery2: Clear undefined buffer before first draw

Clear undefined buffer before first draw.

Crs-fixed: 526603 523916
Change-Id: I1cfdb621bdcf08dc8994adddb0111a1aaf941f56
diff --git a/src/com/android/gallery3d/ui/GLRootView.java b/src/com/android/gallery3d/ui/GLRootView.java
index f00bd54..10aaac7 100644
--- a/src/com/android/gallery3d/ui/GLRootView.java
+++ b/src/com/android/gallery3d/ui/GLRootView.java
@@ -339,6 +339,9 @@
 
     @Override
     public void onDrawFrame(GL10 gl) {
+        //clear the undefined buffer before draw
+        mCanvas.clearBuffer();
+
         AnimationTime.update();
         long t0;
         if (DEBUG_PROFILE_SLOW_ONLY) {