Polish launcher tooltip visibility (2nd try).

ash/launcher/launcher.h

Index: ash/launcher/launcher.h
diff --git a/ash/launcher/launcher.h b/ash/launcher/launcher.h
index 890ea36ad9ff3d98c0088be8d419f690aed7ebca..4f1b376ef3b5c7c0af85a428389908f287282170 100644
--- a/ash/launcher/launcher.h
+++ b/ash/launcher/launcher.h
@@ -32,6 +32,7 @@ namespace ash {
 namespace internal {
 class FocusCycler;
 class LauncherView;
+class ShelfLayoutManager;
 }
 
 class LauncherIconObserver;
@@ -40,7 +41,8 @@ class LauncherModel;
 
 class ASH_EXPORT Launcher : public internal::BackgroundAnimatorDelegate {
  public:
-  explicit Launcher(aura::Window* window_container);
+  Launcher(aura::Window* window_container,
+           internal::ShelfLayoutManager* shelf_layout_manager);
   virtual ~Launcher();
 
   // Sets the focus cycler.  Also adds the launcher to the cycle.