cc : Fix damage rect bug caused by deletion of render surface

cc/trees/damage_tracker.cc

Index: cc/trees/damage_tracker.cc
diff --git a/cc/trees/damage_tracker.cc b/cc/trees/damage_tracker.cc
index 6a8891bf5af14e69c61f471ddb626ad44c6659a0..c56133a88658d3723068932e528c69e8047f0242 100644
--- a/cc/trees/damage_tracker.cc
+++ b/cc/trees/damage_tracker.cc
@@ -280,8 +280,13 @@ void DamageTracker::ExtendDamageForLayer(LayerImpl* layer,
   RectMapData& data = RectDataForLayer(layer->id(), &layer_is_new);
   gfx::Rect old_rect_in_target_space = data.rect_;
 
+  if (!layer_is_new && data.is_render_surface_) {
+    // This was a render surface in the previous frame. Since the surface is now
+    // removed, we need to add it the damage rect.
+    target_damage_rect->Union(data.rect_);
+  }
   gfx::Rect rect_in_target_space = layer->GetEnclosingRectInTargetSpace();
-  data.Update(rect_in_target_space, mailboxId_);
+  data.Update(rect_in_target_space, mailboxId_, false /*is_render_surface*/);
 
   if (layer_is_new || layer->LayerPropertyChanged()) {
     // If a layer is new or has changed, then its entire layer rect affects the
@@ -333,7 +338,8 @@ void DamageTracker::ExtendDamageForRenderSurface(
   // The drawableContextRect() already includes the replica if it exists.
   gfx::Rect surface_rect_in_target_space =
       gfx::ToEnclosingRect(render_surface->DrawableContentRect());
-  data.Update(surface_rect_in_target_space, mailboxId_);
+  data.Update(surface_rect_in_target_space, mailboxId_,
+              true /*is_render_surface*/);
 
   if (surface_is_new || render_surface->SurfacePropertyChanged()) {
     // The entire surface contributes damage.
@@ -376,7 +382,8 @@ void DamageTracker::ExtendDamageForRenderSurface(
         render_surface->replica_draw_transform();
     gfx::Rect replica_mask_layer_rect = MathUtil::MapEnclosingClippedRect(
         replica_draw_transform, gfx::Rect(replica_mask_layer->bounds()));
-    data.Update(replica_mask_layer_rect, mailboxId_);
+    data.Update(replica_mask_layer_rect, mailboxId_,
+                false /*is_render_surface*/);
 
     // In the current implementation, a change in the replica mask damages the
     // entire replica region.