Add support for (de)serializing LayerSelection.

cc/input/layer_selection_bound.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 CC_INPUT_LAYER_SELECTION_BOUND_H_
 #define CC_INPUT_LAYER_SELECTION_BOUND_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/input/selection.h"
 #include "cc/input/selection_bound_type.h"
 #include "ui/gfx/geometry/point.h"
 
 namespace cc {
 
 namespace proto {
+class LayerSelection;
 class LayerSelectionBound;
 }  // namespace proto
 
 // Marker for a selection end-point attached to a specific layer.
 struct CC_EXPORT LayerSelectionBound {
   LayerSelectionBound();
   ~LayerSelectionBound();
 
   SelectionBoundType type;
   gfx::Point edge_top;
   gfx::Point edge_bottom;
   int layer_id;
 
   bool operator==(const LayerSelectionBound& other) const;
   bool operator!=(const LayerSelectionBound& other) const;
 
   void ToProtobuf(proto::LayerSelectionBound* proto) const;
   void FromProtobuf(const proto::LayerSelectionBound& proto);
 };
 
 typedef Selection<LayerSelectionBound> LayerSelection;
 
+CC_EXPORT void LayerSelectionToProtobuf(const LayerSelection& selection,
+                                        proto::LayerSelection* proto);
+CC_EXPORT void LayerSelectionFromProtobuf(LayerSelection* selection,
+                                          const proto::LayerSelection& proto);
+
 }  // namespace cc
 
 #endif  // CC_INPUT_LAYER_SELECTION_BOUND_H_