cc/blimp: Set up the framework for state serialization.

cc/blimp/compositor_state_deserializer.h

+// Copyright 2016 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_BLIMP_COMPOSITOR_STATE_DESERIALIZER_H_
+#define CC_BLIMP_COMPOSITOR_STATE_DESERIALIZER_H_
+
+#include <unordered_map>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "cc/base/cc_export.h"
+
+namespace cc {
+namespace proto {
+class LayerNode;
+class LayerProperties;
+class LayerTree;
+class LayerTreeHost;
+}  // namespace proto
+
+class CompositorStateDeserializerClient;
+class Layer;
+class LayerTreeHost;
+
+// Deserializes the compositor updates into the LayerTreeHost.
+class CC_EXPORT CompositorStateDeserializer {
+ public:
+  // ScrollCallback used to notify the client when the scroll offset for a layer
+  // is updated.
+  using ScrollCallback = base::Callback<void(int engine_layer_id)>;
+
+  CompositorStateDeserializer(LayerTreeHost* layer_tree_host,
+                              ScrollCallback scroll_callback,
+                              CompositorStateDeserializerClient* client);
+  ~CompositorStateDeserializer();
+
+  // Returns the local layer on the client for the given |engine_layer_id|.
+  Layer* GetLayerForEngineId(int engine_layer_id) const;
+
+  // Deserializes the |layer_tree_host_proto| into the LayerTreeHost.
+  void DeserializeCompositorUpdate(
+      const proto::LayerTreeHost& layer_tree_host_proto);
+
+ private:
+  using EngineIdToLayerMap = std::unordered_map<int, scoped_refptr<Layer>>;
+
+  void SychronizeLayerTreeState(const proto::LayerTree& layer_tree_proto);
+  void SynchronizeLayerState(
+      const proto::LayerProperties& layer_properties_proto);
+  void SynchronizeLayerHeirarchyRecursive(Layer* layer,
+                                          const proto::LayerNode& layer_node,
+                                          EngineIdToLayerMap* new_layer_map);
+  scoped_refptr<Layer> GetLayerAndAddToNewMap(
+      const proto::LayerNode& layer_node,
+      EngineIdToLayerMap* new_layer_map);
+
+  int GetClientIdFromEngineId(int engine_layer_id);
+  scoped_refptr<Layer> GetLayer(int engine_layer_id);
+
+  LayerTreeHost* layer_tree_host_;
+  ScrollCallback scroll_callback_;
+  CompositorStateDeserializerClient* client_;
+
+  EngineIdToLayerMap engine_id_to_layer_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompositorStateDeserializer);
+};
+
+}  // namespace cc
+
+#endif  // CC_BLIMP_COMPOSITOR_STATE_DESERIALIZER_H_