[tracing] Implement composable memory usage estimators.

cc/resources/ui_resource_bitmap.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_UI_RESOURCE_BITMAP_H_
 #define CC_RESOURCES_UI_RESOURCE_BITMAP_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 34 matching lines @@
 
   // User must ensure that |skbitmap| is immutable.  The SkBitmap Format should
   // be 32-bit RGBA or 8-bit ALPHA.
   explicit UIResourceBitmap(const SkBitmap& skbitmap);
   UIResourceBitmap(const gfx::Size& size, bool is_opaque);
   UIResourceBitmap(sk_sp<SkPixelRef> pixel_ref, const gfx::Size& size);
   UIResourceBitmap(const UIResourceBitmap& other);
   ~UIResourceBitmap();
 
   // Returns the memory usage of the bitmap.
-  size_t GetAllocatedSizeInBytes() const {
+  size_t EstimateMemoryUsage() const {
     return pixel_ref_ ? pixel_ref_->rowBytes() * size_.height() : 0;
   }
 
  private:
   friend class AutoLockUIResourceBitmap;
 
   void Create(sk_sp<SkPixelRef> pixel_ref,
               const gfx::Size& size,
               UIResourceFormat format);
 
   sk_sp<SkPixelRef> pixel_ref_;
   UIResourceFormat format_;
   gfx::Size size_;
   bool opaque_;
 };
 
 class CC_EXPORT AutoLockUIResourceBitmap {
  public:
   explicit AutoLockUIResourceBitmap(const UIResourceBitmap& bitmap);
   ~AutoLockUIResourceBitmap();
   const uint8_t* GetPixels() const;
 
  private:
   const UIResourceBitmap& bitmap_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_UI_RESOURCE_BITMAP_H_