[tracing] Implement composable memory usage estimators.

cc/resources/scoped_ui_resource.h

 // Copyright 2013 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_RESOURCES_SCOPED_UI_RESOURCE_H_
 #define CC_RESOURCES_SCOPED_UI_RESOURCE_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "cc/base/cc_export.h"
@@ skipping 15 matching lines @@
   static std::unique_ptr<ScopedUIResource> Create(
       UIResourceManager* ui_resource_manager,
       const UIResourceBitmap& bitmap);
   ~ScopedUIResource() override;
 
   // UIResourceClient implementation.
   UIResourceBitmap GetBitmap(UIResourceId uid, bool resource_lost) override;
   UIResourceId id() { return id_; }
 
   // Returns the memory usage of the bitmap.
-  size_t GetAllocatedSizeInBytes() const {
-    return bitmap_.GetAllocatedSizeInBytes();
-  }
+  size_t EstimateMemoryUsage() const { return bitmap_.EstimateMemoryUsage(); }
 
  protected:
   ScopedUIResource(UIResourceManager* ui_resource_manager,
                    const UIResourceBitmap& bitmap);
 
   UIResourceBitmap bitmap_;
   UIResourceManager* ui_resource_manager_;
   UIResourceId id_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedUIResource);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_SCOPED_UI_RESOURCE_H_