Refactors maximize mode event handling into its own class

ash/common/wm/maximize_mode/maximize_mode_event_handler.h

+// Copyright 2016 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_COMMON_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_EVENT_HANDLER_H_
+#define ASH_COMMON_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_EVENT_HANDLER_H_
+
+#include "base/macros.h"
+
+namespace ui {
+class TouchEvent;
+}
+
+namespace ash {
+namespace wm {
+
+// MaximizeModeEventHandler handles toggling fullscreen when appropriate.
+// MaximizeModeEventHandler installs event handlers in an environment specific
+// way, e.g. EventHandler for aura.
+class MaximizeModeEventHandler {
+ public:
+  MaximizeModeEventHandler();
+  virtual ~MaximizeModeEventHandler();
+
+ protected:
+  // Subclasses call this to toggle fullscreen. If a toggle happened returns
+  // true.
+  bool ToggleFullscreen(const ui::TouchEvent& event);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MaximizeModeEventHandler);
+};
+
+}  // namespace wm
+}  // namespace ash
+
+#endif  // ASH_COMMON_WM_MAXIMIZE_MODE_MAXIMIZE_MODE_EVENT_HANDLER_H_