Converts RootWindowLayoutManager to common types

ash/root_window_controller_common.h

Index: ash/root_window_controller_common.h
diff --git a/ash/root_window_controller_common.h b/ash/root_window_controller_common.h
index 4a0b8b40e188659132f42a1c27ef8e7f42ef829f..c89e8df32f39cbc6b37a22bb6d7196af72584efe 100644
--- a/ash/root_window_controller_common.h
+++ b/ash/root_window_controller_common.h
@@ -9,6 +9,7 @@
 
 namespace ash {
 namespace wm {
+class RootWindowLayoutManager;
 class WmWindow;
 }
 
@@ -23,9 +24,18 @@ class RootWindowControllerCommon {
   // Creates the containers (WmWindows) used by the shell.
   void CreateContainers();
 
+  // Creates the LayoutManagers for the windows created by CreateContainers().
+  void CreateLayoutManagers();
+
+  wm::RootWindowLayoutManager* root_window_layout() {
+    return root_window_layout_;
+  }
+
  private:
   wm::WmWindow* root_;
 
+  wm::RootWindowLayoutManager* root_window_layout_;
+
   DISALLOW_COPY_AND_ASSIGN(RootWindowControllerCommon);
 };