Converts overview to use common ash types

ash/wm/common/wm_globals.h

Index: ash/wm/common/wm_globals.h
diff --git a/ash/wm/common/wm_globals.h b/ash/wm/common/wm_globals.h
index b58b331f11f90c02d8edcec3ebbb4fcc41c5ba6d..0e5549955e5e5cae07d324b1e3a67c3b160836db 100644
--- a/ash/wm/common/wm_globals.h
+++ b/ash/wm/common/wm_globals.h
@@ -43,6 +43,8 @@ class ASH_WM_COMMON_EXPORT WmGlobals {
   virtual WmWindow* GetFocusedWindow() = 0;
   virtual WmWindow* GetActiveWindow() = 0;
 
+  virtual WmWindow* GetPrimaryRootWindow() = 0;
+
   // Returns the root window for the specified display.
   virtual WmWindow* GetRootWindowForDisplayId(int64_t display_id) = 0;
 
@@ -51,7 +53,10 @@ class ASH_WM_COMMON_EXPORT WmGlobals {
   // appropriate container in the returned window.
   virtual WmWindow* GetRootWindowForNewWindows() = 0;
 
-  // returns the list of more recently used windows excluding modals.
+  // Returns the list of more recently used windows.

[James Cook, 2016/05/27 00:02:51]

super-nit: *most* recently used

[sky, 2016/05/27 03:18:03]

Done.

+  virtual std::vector<WmWindow*> GetMruWindowList() = 0;
+
+  // Returns the list of more recently used windows excluding modals.
   virtual std::vector<WmWindow*> GetMruWindowListIgnoreModals() = 0;
 
   // Returns true if the first window shown on first run should be