Revert of Split Screen mode implementation

athena/wm/window_overview_mode.h

Index: athena/wm/window_overview_mode.h
diff --git a/athena/wm/window_overview_mode.h b/athena/wm/window_overview_mode.h
index a95a0fb648a4dc6f440e14c645d560f121455eac..46eb249031eecb1caad16efa236df9153709ae9b 100644
--- a/athena/wm/window_overview_mode.h
+++ b/athena/wm/window_overview_mode.h
@@ -6,10 +6,12 @@
 #define ATHENA_WM_WINDOW_OVERVIEW_MODE_H_
 
 #include "base/memory/scoped_ptr.h"
-#include "ui/aura/window.h"
+
+namespace aura {
+class Window;
+}
 
 namespace athena {
-class WindowListProvider;
 
 class WindowOverviewModeDelegate {
  public:
@@ -24,7 +26,6 @@
 
   static scoped_ptr<WindowOverviewMode> Create(
       aura::Window* container,
-      const WindowListProvider* window_list_provider,
       WindowOverviewModeDelegate* delegate);
 };