Adds a ServerViewObserver interface

services/view_manager/server_view.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 SERVICES_VIEW_MANAGER_SERVER_VIEW_H_
 #define SERVICES_VIEW_MANAGER_SERVER_VIEW_H_
 
 #include <vector>
 
 #include "base/logging.h"
+#include "base/observer_list.h"
 #include "cc/surfaces/surface_id.h"
 #include "mojo/services/view_manager/public/interfaces/view_manager.mojom.h"
 #include "services/view_manager/ids.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/transform.h"
 
 namespace view_manager {
 
 class ServerViewDelegate;
+class ServerViewObserver;
 
 // Server side representation of a view. Delegate is informed of interesting
 // events.
 //
 // It is assumed that all functions that mutate the tree have validated the
 // mutation is possible before hand. For example, Reorder() assumes the supplied
 // view is a child and not already in position.
 class ServerView {
  public:
   ServerView(ServerViewDelegate* delegate, const ViewId& id);
   virtual ~ServerView();
 
+  void AddObserver(ServerViewObserver* observer);
+  void RemoveObserver(ServerViewObserver* observer);
+
   const ViewId& id() const { return id_; }
 
   void Add(ServerView* child);
   void Remove(ServerView* child);
   void Reorder(ServerView* child,
                ServerView* relative,
                mojo::OrderDirection direction);
 
   const gfx::Rect& bounds() const { return bounds_; }
   void SetBounds(const gfx::Rect& bounds);
@@ skipping 52 matching lines @@
   ServerView* parent_;
   Views children_;
   bool visible_;
   gfx::Rect bounds_;
   cc::SurfaceId surface_id_;
   float opacity_;
   gfx::Transform transform_;
 
   std::map<std::string, std::vector<uint8_t>> properties_;
 
+  ObserverList<ServerViewObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(ServerView);
 };
 
 }  // namespace view_manager
 
 #endif  // SERVICES_VIEW_MANAGER_SERVER_VIEW_H_