HUD: Show first paint invalidation in red

cc/debug/debug_rect_history.h

 // Copyright 2012 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_DEBUG_DEBUG_RECT_HISTORY_H_
 #define CC_DEBUG_DEBUG_RECT_HISTORY_H_
 
 #include <vector>
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 25 matching lines @@
 // occupy in screen space.
 //
 // - Occluding rects: these are the regions that contribute to the occluded
 // region.
 //
 // - Non-Occluding rects: these are the regions of composited layers that do not
 //   contribute to the occluded region.
 //
 enum DebugRectType {
   PAINT_RECT_TYPE,
+  FIRST_PAINT_RECT_TYPE,
   PROPERTY_CHANGED_RECT_TYPE,
   SURFACE_DAMAGE_RECT_TYPE,
   SCREEN_SPACE_RECT_TYPE,
   REPLICA_SCREEN_SPACE_RECT_TYPE,
   OCCLUDING_RECT_TYPE,
   NONOCCLUDING_RECT_TYPE,
   TOUCH_EVENT_HANDLER_RECT_TYPE,
   WHEEL_EVENT_HANDLER_RECT_TYPE,
   SCROLL_EVENT_HANDLER_RECT_TYPE,
   NON_FAST_SCROLLABLE_RECT_TYPE,
@@ skipping 55 matching lines @@
       const LayerImplList& render_surface_layer_list);
 
   std::vector<DebugRect> debug_rects_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugRectHistory);
 };
 
 }  // namespace cc
 
 #endif  // CC_DEBUG_DEBUG_RECT_HISTORY_H_