Replace WmWindowObserver with aura::WindowObserver.

ash/common/wm/workspace/workspace_window_resizer.h

 // Copyright (c) 2012 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 ASH_COMMON_WM_WORKSPACE_WORKSPACE_WINDOW_RESIZER_H_
 #define ASH_COMMON_WM_WORKSPACE_WORKSPACE_WINDOW_RESIZER_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "ash/common/wm/window_resizer.h"
 #include "ash/common/wm/workspace/magnetism_matcher.h"
-#include "ash/common/wm_window_tracker.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "ui/aura/window_tracker.h"
 
 namespace ash {
 class DockedWindowLayoutManager;
 class PhantomWindowController;
 class TwoStepEdgeCycler;
 class WindowSize;
+class WmShell;
 
 namespace wm {
 class WindowState;
-class WmShell;
 }
 
 // WindowResizer implementation for workspaces. This enforces that windows are
 // not allowed to vertically move or resize outside of the work area. As windows
 // are moved outside the work area they are shrunk. We remember the height of
 // the window before it was moved so that if the window is again moved up we
 // attempt to restore the old height.
 class ASH_EXPORT WorkspaceWindowResizer : public WindowResizer {
  public:
   // When dragging an attached window this is the min size we'll make sure is
@@ skipping 163 matching lines @@
   // the screen.
   int num_mouse_moves_since_bounds_change_;
 
   // The mouse location passed to Drag().
   gfx::Point last_mouse_location_;
 
   // Window the drag has magnetically attached to.
   WmWindow* magnetism_window_;
 
   // Used to verify |magnetism_window_| is still valid.
-  WmWindowTracker window_tracker_;
+  aura::WindowTracker window_tracker_;
 
   // If |magnetism_window_| is non-NULL this indicates how the two windows
   // should attach.
   MatchedEdge magnetism_edge_;
 
   // Dock container window layout manager.
   DockedWindowLayoutManager* dock_layout_;
 
   // Used to determine if this has been deleted during a drag such as when a tab
   // gets dragged into another browser window.
   base::WeakPtrFactory<WorkspaceWindowResizer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceWindowResizer);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_WORKSPACE_WORKSPACE_WINDOW_RESIZER_H_