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

cc/trees/damage_tracker.h

 // Copyright 2011 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.
 
 #ifndef CC_TREES_DAMAGE_TRACKER_H_
 #define CC_TREES_DAMAGE_TRACKER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 46 matching lines @@
   gfx::Rect TrackDamageFromLeftoverRects();
 
   void PrepareRectHistoryForUpdate();
 
   // These helper functions are used only in TrackDamageFromActiveLayers().
   void ExtendDamageForLayer(LayerImpl* layer, gfx::Rect* target_damage_rect);
   void ExtendDamageForRenderSurface(LayerImpl* layer,
                                     gfx::Rect* target_damage_rect);
 
   struct RectMapData {
-    RectMapData() : layer_id_(0), mailboxId_(0) {}
-    explicit RectMapData(int layer_id) : layer_id_(layer_id), mailboxId_(0) {}
-    void Update(const gfx::Rect& rect, unsigned int mailboxId) {
+    RectMapData() : layer_id_(0), mailboxId_(0), is_render_surface_(false) {}

[ajuma, 2016/05/16 15:16:21]

How about splitting the map in two, one map for layers and one for surfaces?
Then a change from surface to layer will be handled for free by the logic in
TrackDamageFromLeftoverRects (since we'll have a leftover rect in the surface
map). It also seems like something we'll need to do eventually anyway, to deal
with surfaces no longer being owned by layers.

[jaydasika, 2016/05/16 19:32:49]

Done.

+    explicit RectMapData(int layer_id)
+        : layer_id_(layer_id), mailboxId_(0), is_render_surface_(false) {}
+    void Update(const gfx::Rect& rect,
+                unsigned int mailboxId,
+                bool is_render_surface) {
       mailboxId_ = mailboxId;
       rect_ = rect;
+      is_render_surface_ = is_render_surface;
     }
 
     bool operator < (const RectMapData& other) const {
       return layer_id_ < other.layer_id_;
     }
 
     int layer_id_;
     unsigned int mailboxId_;
+    bool is_render_surface_;
     gfx::Rect rect_;
   };
   typedef std::vector<RectMapData> SortedRectMap;
 
   RectMapData& RectDataForLayer(int layer_id, bool* layer_is_new);
 
   SortedRectMap rect_history_;
 
   unsigned int mailboxId_;
   gfx::Rect current_damage_rect_;
 
   DISALLOW_COPY_AND_ASSIGN(DamageTracker);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_DAMAGE_TRACKER_H_