Removes most aura dependencies from WindowResizer

ash/wm/common/wm_root_window_controller.h

Index: ash/wm/common/wm_root_window_controller.h
diff --git a/ash/wm/common/wm_root_window_controller.h b/ash/wm/common/wm_root_window_controller.h
index a2b06ddc85799f0dacf6d2307983634137c890fd..e247c0888b6fb11012b7a84df5b7fa414bffdb78 100644
--- a/ash/wm/common/wm_root_window_controller.h
+++ b/ash/wm/common/wm_root_window_controller.h
@@ -5,6 +5,8 @@
 #ifndef ASH_WM_COMMON_WM_ROOT_CONTROLLER_H_
 #define ASH_WM_COMMON_WM_ROOT_CONTROLLER_H_
 
+#include <stdint.h>
+
 #include "ash/ash_export.h"
 #include "ash/wm/common/workspace/workspace_types.h"
 
@@ -14,15 +16,21 @@ namespace wm {
 class WmGlobals;
 class WmWindow;
 
+// Provides state associated with a root of a window hierarchy.
 class ASH_EXPORT WmRootWindowController {
  public:
   virtual ~WmRootWindowController() {}
 
+  static WmRootWindowController* GetWithDisplayId(int64_t id);
+
   virtual bool HasShelf() = 0;
 
   virtual WmGlobals* GetGlobals() = 0;
 
   virtual WorkspaceWindowState GetWorkspaceWindowState() = 0;
+
+  // Returns the window associated with this WmRootWindowController.
+  virtual WmWindow* GetWindow() = 0;
 };
 
 }  // namespace wm