Serialize PictureLayer properties.

cc/layers/empty_content_layer_client.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_LAYERS_EMPTY_CONTENT_LAYER_CLIENT_H_
+#define CC_LAYERS_EMPTY_CONTENT_LAYER_CLIENT_H_
+
+#include "base/lazy_instance.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "cc/base/cc_export.h"
+#include "cc/layers/content_layer_client.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace cc {
+
+class DisplayItemList;
+
+// This is used by deserialized PictureLayers which have no local
+// ContentLayerClient but still have valid content from the original serialized
+// PictureLayer.  The PictureLayer class requires a valid ContentLayerClient to
+// determine if it can draw.  This is a dummy client to keep the logic fairly
+// straightforward.  This is also used by unit tests for creating dummy
+// PictureLayers.
+class CC_EXPORT EmptyContentLayerClient : public ContentLayerClient {
+ public:
+  static ContentLayerClient* GetInstance();
+
+  // ContentLayerClient implementation.
+  gfx::Rect PaintableRegion() override;
+  scoped_refptr<DisplayItemList> PaintContentsToDisplayList(
+      PaintingControlSetting painting_status) override;
+  bool FillsBoundsCompletely() const override;
+  size_t GetApproximateUnsharedMemoryUsage() const override;
+
+ private:
+  friend struct base::DefaultLazyInstanceTraits<EmptyContentLayerClient>;
+
+  EmptyContentLayerClient();
+  ~EmptyContentLayerClient() override;
+
+  DISALLOW_COPY_AND_ASSIGN(EmptyContentLayerClient);
+};
+
+}  // namespace cc
+
+#endif  // CC_LAYERS_EMPTY_CONTENT_LAYER_CLIENT_H_