Add WorkspaceObserver to observe changes in workspace state

ui/aura_shell/workspace/workspace_controller.h

 // Copyright (c) 2011 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 UI_AURA_SHELL_WORKSPACE_WORKSPACE_CONTROLLER_H_
 #define UI_AURA_SHELL_WORKSPACE_WORKSPACE_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/desktop_observer.h"
@@ skipping 10 matching lines @@
 namespace aura_shell {
 namespace internal {
 
 class DefaultContainerLayoutManager;
 class WorkspaceManager;
 
 // WorkspaceControlls owns a WorkspaceManager. WorkspaceControlls bridges
 // events From DesktopObserver translating them to WorkspaceManager.
 class AURA_SHELL_EXPORT WorkspaceController : public aura::DesktopObserver {
  public:
-  explicit WorkspaceController(aura::Window* window);
+  explicit WorkspaceController(aura::Window* workspace_viewport);
   virtual ~WorkspaceController();
 
   void ToggleOverview();
 
-  internal::DefaultContainerLayoutManager* layout_manager() {
-    return layout_manager_;
+  // Returns the workspace manager that this controler owns.
+  WorkspaceManager* workspace_manager() {
+    return workspace_manager_.get();
   }
 
   // DesktopObserver overrides:
   virtual void OnDesktopResized(const gfx::Size& new_size) OVERRIDE;
   virtual void OnActiveWindowChanged(aura::Window* active) OVERRIDE;
 
  private:
   scoped_ptr<WorkspaceManager> workspace_manager_;
 
-  // This is owned by the window it's installed on.
-  internal::DefaultContainerLayoutManager* layout_manager_;
-
   DISALLOW_COPY_AND_ASSIGN(WorkspaceController);
 };
 
 }  // namespace internal
 }  // namespace aura_shell
 
 #endif  // UI_AURA_SHELL_WORKSPACE_WORKSPACE_CONTROLLER_H_