Moves ToastManager from Shell to WmShell

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 30aa8ad5b0fd1402f3c0a038e4e341e6d431c959..5a1fdaf1b213e7775ce68165eaa212a320943e04 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -138,7 +138,6 @@ class StickyKeysController;
 class SystemGestureEventFilter;
 class SystemModalContainerEventFilter;
 class SystemTray;
-class ToastManager;
 class ToplevelWindowEventHandler;
 class TouchTransformerController;
 class TouchObserverHUD;
@@ -518,8 +517,6 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
     return screen_pinning_controller_.get();
   }
 
-  ToastManager* toast_manager() { return toast_manager_.get(); }
-
   GPUSupport* gpu_support() { return gpu_support_.get(); }
 
  private:
@@ -682,8 +679,6 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
   std::unique_ptr<ui::EventHandler> speech_feedback_handler_;
 #endif  // defined(OS_CHROMEOS)
 
-  std::unique_ptr<ToastManager> toast_manager_;
-
   // |native_cursor_manager_| is owned by |cursor_manager_|, but we keep a
   // pointer to vend to test code.
   AshNativeCursorManager* native_cursor_manager_;