Force use of and cache render surface.

cc/trees/damage_tracker.h

Index: cc/trees/damage_tracker.h
diff --git a/cc/trees/damage_tracker.h b/cc/trees/damage_tracker.h
index 5ad62c896001bb8c410f19fa1b69d42ddf5a7611..c320db4335030e528d6ddb371fb8623be5807d99 100644
--- a/cc/trees/damage_tracker.h
+++ b/cc/trees/damage_tracker.h
@@ -36,11 +36,18 @@ class CC_EXPORT DamageTracker {
       LayerTreeImpl* layer_tree_impl,
       const RenderSurfaceList& render_surface_list);
 
-  void DidDrawDamagedArea() { current_damage_ = DamageAccumulator(); }
+  void DidDrawDamagedArea() {
+    current_damage_ = DamageAccumulator();
+    has_damage_from_contributing_content_ = false;
+  }
   void AddDamageNextUpdate(const gfx::Rect& dmg) { current_damage_.Union(dmg); }
 
   bool GetDamageRectIfValid(gfx::Rect* rect);
 
+  bool has_damage_from_contributing_content() const {
+    return has_damage_from_contributing_content_;
+  }
+
  private:
   DamageTracker();
 
@@ -141,6 +148,8 @@ class CC_EXPORT DamageTracker {
 
   unsigned int mailboxId_;
   DamageAccumulator current_damage_;
+  // Damage from contributing render surface and layer
+  bool has_damage_from_contributing_content_;
 
   // Damage accumulated since the last call to PrepareForUpdate().
   DamageAccumulator damage_for_this_update_;