Adds a ServerViewObserver interface

services/view_manager/server_view_observer.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// 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 SERVICES_VIEW_MANAGER_SERVER_VIEW_DELEGATE_H_
-#define SERVICES_VIEW_MANAGER_SERVER_VIEW_DELEGATE_H_
+#ifndef SERVICES_VIEW_MANAGER_SERVER_VIEW_OBSERVER_H_
+#define SERVICES_VIEW_MANAGER_SERVER_VIEW_OBSERVER_H_
 
 #include "mojo/services/view_manager/public/interfaces/view_manager_constants.mojom.h"
 
 namespace gfx {
 class Rect;
 }
 
 namespace mojo {
 class ViewportMetrics;
 }
 
 namespace view_manager {
 
 class ServerView;
 
-class ServerViewDelegate {
+class ServerViewObserver {
  public:
   // Invoked when a view is about to be destroyed; before any of the children
   // have been removed and before the view has been removed from its parent.
-  virtual void OnWillDestroyView(ServerView* view) = 0;
+  virtual void OnWillDestroyView(const ServerView* view) {}
 
   // Invoked at the end of the View's destructor (after it has been removed from
   // the hierarchy).
-  virtual void OnViewDestroyed(const ServerView* view) = 0;
+  virtual void OnViewDestroyed(const ServerView* view) {}
 
-  virtual void OnWillChangeViewHierarchy(ServerView* view,
-                                         ServerView* new_parent,
-                                         ServerView* old_parent) = 0;
+  virtual void OnWillChangeViewHierarchy(const ServerView* view,
+                                         const ServerView* new_parent,
+                                         const ServerView* old_parent) {}
 
   virtual void OnViewHierarchyChanged(const ServerView* view,
                                       const ServerView* new_parent,
-                                      const ServerView* old_parent) = 0;
+                                      const ServerView* old_parent) {}
 
   virtual void OnViewBoundsChanged(const ServerView* view,
                                    const gfx::Rect& old_bounds,
-                                   const gfx::Rect& new_bounds) = 0;
-
-  virtual void OnViewSurfaceIdChanged(const ServerView* view) = 0;
+                                   const gfx::Rect& new_bounds) {}
 
   virtual void OnViewReordered(const ServerView* view,
                                const ServerView* relative,
-                               mojo::OrderDirection direction) = 0;
+                               mojo::OrderDirection direction) {}
 
-  virtual void OnWillChangeViewVisibility(ServerView* view) = 0;
+  virtual void OnWillChangeViewVisibility(const ServerView* view) {}
 
   virtual void OnViewSharedPropertyChanged(
       const ServerView* view,
       const std::string& name,
-      const std::vector<uint8_t>* new_data) = 0;
-
-  virtual void OnScheduleViewPaint(const ServerView* view) = 0;
+      const std::vector<uint8_t>* new_data) {}
 
  protected:
-  virtual ~ServerViewDelegate() {}
+  virtual ~ServerViewObserver() {}
 };
 
 }  // namespace view_manager
 
-#endif  // SERVICES_VIEW_MANAGER_SERVER_VIEW_DELEGATE_H_
+#endif  // SERVICES_VIEW_MANAGER_SERVER_VIEW_OBSERVER_H_