cc: Devirtualize DisplayItem::ExternalMemoryUsage().

cc/playback/compositing_display_item.h

 // Copyright 2015 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_COMPOSITING_DISPLAY_ITEM_H_
 #define CC_PLAYBACK_COMPOSITING_DISPLAY_ITEM_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 19 matching lines @@
                          sk_sp<SkColorFilter> color_filter,
                          bool lcd_text_requires_opaque_layer);
   explicit CompositingDisplayItem(const proto::DisplayItem& proto);
   ~CompositingDisplayItem() override;
 
   void ToProtobuf(proto::DisplayItem* proto) const override;
   void Raster(SkCanvas* canvas,
               SkPicture::AbortCallback* callback) const override;
   void AsValueInto(const gfx::Rect& visual_rect,
                    base::trace_event::TracedValue* array) const override;
-  size_t ExternalMemoryUsage() const override;
 
+  size_t ExternalMemoryUsage() const {
+    // TODO(pdr): Include color_filter's memory here.
+    return 0;
+  }
   int ApproximateOpCount() const { return 1; }
 
  private:
   void SetNew(uint8_t alpha,
               SkBlendMode xfermode,
               SkRect* bounds,
               sk_sp<SkColorFilter> color_filter,
               bool lcd_text_requires_opaque_layer);
 
   uint8_t alpha_;
@@ skipping 12 matching lines @@
 
   static std::unique_ptr<EndCompositingDisplayItem> Create() {
     return base::MakeUnique<EndCompositingDisplayItem>();
   }
 
   void ToProtobuf(proto::DisplayItem* proto) const override;
   void Raster(SkCanvas* canvas,
               SkPicture::AbortCallback* callback) const override;
   void AsValueInto(const gfx::Rect& visual_rect,
                    base::trace_event::TracedValue* array) const override;
-  size_t ExternalMemoryUsage() const override;
 
   int ApproximateOpCount() const { return 0; }
 };
 
 }  // namespace cc
 
 #endif  // CC_PLAYBACK_COMPOSITING_DISPLAY_ITEM_H_