cc/blimp: Add a LayerTreeHostRemote implementation.

cc/trees/layer_tree_host.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_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "cc/base/cc_export.h"
@@ skipping 36 matching lines @@
   // update(commit) pushed to the compositor thread.
   virtual int SourceFrameNumber() const = 0;
 
   // Returns the LayerTree that holds the main frame state pushed to the
   // LayerTreeImpl on commit.
   virtual LayerTree* GetLayerTree() = 0;
   virtual const LayerTree* GetLayerTree() const = 0;
 
   // Returns the UIResourceManager used to create UIResources for
   // UIResourceLayers pushed to the LayerTree.
-  virtual UIResourceManager* GetUIResourceManager() const = 0;
+  virtual UIResourceManager* GetUIResourceManager() = 0;
 
   // Returns the TaskRunnerProvider used to access the main and compositor
   // thread task runners.
   virtual TaskRunnerProvider* GetTaskRunnerProvider() const = 0;
 
   // Returns the settings used by this host.
   virtual const LayerTreeSettings& GetSettings() const = 0;
 
   // Sets the client id used to generate the SurfaceId that uniquely identifies
   // the Surfaces produced by this compositor.
@@ skipping 124 matching lines @@
 
   // When the main thread informs the impl thread that it is ready to commit,
   // generally it would remain blocked till the main thread state is copied to
   // the pending tree. Calling this would ensure that the main thread remains
   // blocked till the pending tree is activated.
   virtual void SetNextCommitWaitsForActivation() = 0;
 
   // The LayerTreeHost tracks whether the content is suitable for Gpu raster.
   // Calling this will reset it back to not suitable state.
   virtual void ResetGpuRasterizationTracking() = 0;
+
+ protected:
+  // Used to generate a unique identifier for a LayerTreeHost.
+  static int GenerateHostId();
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_