Revert of cc: Build Image to Region map during image meta-data generation.

cc/playback/display_item_list.h

 // Copyright 2014 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_PLAYBACK_DISPLAY_ITEM_LIST_H_
 #define CC_PLAYBACK_DISPLAY_ITEM_LIST_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 139 matching lines @@
 
   std::unique_ptr<base::trace_event::ConvertableToTraceFormat> AsValue(
       bool include_items) const;
 
   void EmitTraceSnapshot() const;
 
   void GenerateDiscardableImagesMetadata();
   void GetDiscardableImagesInRect(const gfx::Rect& rect,
                                   const gfx::SizeF& raster_scales,
                                   std::vector<DrawImage>* images);
-  Region GetRegionForImage(uint32_t image_id);
 
   void SetRetainVisualRectsForTesting(bool retain) {
     retain_visual_rects_ = retain;
   }
 
   size_t size() const { return inputs_.items.size(); }
 
   gfx::Rect VisualRectForTesting(int index) {
     return inputs_.visual_rects[index];
   }
@@ skipping 51 matching lines @@
   Inputs inputs_;
 
   friend class base::RefCountedThreadSafe<DisplayItemList>;
   FRIEND_TEST_ALL_PREFIXES(DisplayItemListTest, ApproximateMemoryUsage);
   DISALLOW_COPY_AND_ASSIGN(DisplayItemList);
 };
 
 }  // namespace cc
 
 #endif  // CC_PLAYBACK_DISPLAY_ITEM_LIST_H_