Add double click and tap handler to minimize attached panels.

ash/wm/panels/panel_window_event_handler.h

Index: ash/wm/panels/panel_window_event_handler.h
diff --git a/ash/wm/panels/panel_window_event_handler.h b/ash/wm/panels/panel_window_event_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..627aa891780eb141a65e3b7658f2655d754e0045
--- /dev/null
+++ b/ash/wm/panels/panel_window_event_handler.h
@@ -0,0 +1,35 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_WM_PANELS_PANEL_WINDOW_EVENT_HANDLER_H_
+#define ASH_WM_PANELS_PANEL_WINDOW_EVENT_HANDLER_H_
+
+#include "ash/wm/toplevel_window_event_handler.h"
+
+namespace aura {
+class Window;
+}
+
+namespace ash {
+namespace internal {
+
+// PanelWindowEventHandler minimizes panels when the user double clicks or
+// double taps on the panel header.
+class PanelWindowEventHandler : public ToplevelWindowEventHandler {
+ public:
+  explicit PanelWindowEventHandler(aura::Window* owner);
+  virtual ~PanelWindowEventHandler();
+
+  // TopLevelWindowEventHandler:
+  virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PanelWindowEventHandler);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_WM_PANELS_PANEL_WINDOW_EVENT_HANDLER_H_