[tracing] Implement composable memory usage estimators.

ui/android/resources/resource_manager.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 UI_ANDROID_RESOURCES_RESOURCE_MANAGER_H_
 #define UI_ANDROID_RESOURCES_RESOURCE_MANAGER_H_
 
 #include <memory>
 #include <unordered_map>
 #include <unordered_set>
@@ skipping 28 matching lines @@
 // The ResourceManager serves as a cache for resources obtained through Android
 // APIs and consumed by the compositor.
 class UI_ANDROID_EXPORT ResourceManager {
  public:
   struct Resource {
    public:
     Resource();
     ~Resource();
     gfx::Rect Border(const gfx::Size& bounds) const;
     gfx::Rect Border(const gfx::Size& bounds, const gfx::InsetsF& scale) const;
+    size_t EstimateMemoryUsage() const;
 
     std::unique_ptr<cc::ScopedUIResource> ui_resource;
     gfx::Size size;
     gfx::Rect padding;
     gfx::Rect aperture;
   };
 
   // Obtain a handle to the Java ResourceManager counterpart.
   virtual base::android::ScopedJavaLocalRef<jobject> GetJavaObject() = 0;
 
@@ skipping 32 matching lines @@
     return resource && resource->ui_resource ? resource->ui_resource->id() : 0;
   }
 
  protected:
   virtual ~ResourceManager() {}
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_RESOURCES_RESOURCE_MANAGER_H_