Move the panel to the root window where the mouse click occurred.

ash/launcher/launcher_delegate.h

Index: ash/launcher/launcher_delegate.h
diff --git a/ash/launcher/launcher_delegate.h b/ash/launcher/launcher_delegate.h
index 1e3288fe15478c90bc5a943f1eb966778c40b8f1..e10c5dc683326320479b130cb419dca8d13b96eb 100644
--- a/ash/launcher/launcher_delegate.h
+++ b/ash/launcher/launcher_delegate.h
@@ -14,6 +14,7 @@ class RootWindow;
 }
 
 namespace ui {
+class Event;
 class MenuModel;
 }
 
@@ -31,8 +32,11 @@ class ASH_EXPORT LauncherDelegate {
   virtual void OnBrowserShortcutClicked(int event_flags) = 0;
 
   // Invoked when the user clicks on a window entry in the launcher.
-  // |event_flags| is the flags of the click event.
-  virtual void ItemClicked(const LauncherItem& item, int event_flags) = 0;
+  // |event| is the click event. The |event| is dispatched by a view
+  // and has an instance of |views::View| as the event target
+  // but not |aura::Window|.
+  virtual void ItemClicked(const LauncherItem& item,
+                           const ui::Event& event) = 0;
 
   // Returns the resource id of the image to show on the browser shortcut
   // button.