Moves WorkspaceEventHandler to ash/common

ash/mus/bridge/workspace_event_handler_mus.h

Index: ash/mus/bridge/workspace_event_handler_mus.h
diff --git a/ash/mus/bridge/workspace_event_handler_mus.h b/ash/mus/bridge/workspace_event_handler_mus.h
new file mode 100644
index 0000000000000000000000000000000000000000..87d1df50a3f9f600c71a5952557172e8d888c906
--- /dev/null
+++ b/ash/mus/bridge/workspace_event_handler_mus.h
@@ -0,0 +1,39 @@
+// 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_MUS_BRIDGE_WORKSPACE_EVENT_HANDLER_MUS_H_
+#define ASH_MUS_BRIDGE_WORKSPACE_EVENT_HANDLER_MUS_H_
+
+#include "ash/common/wm/workspace/workspace_event_handler.h"
+#include "base/macros.h"
+
+namespace ui {
+class Window;
+}
+
+namespace ash {
+namespace mus {
+
+class WorkspaceEventHandlerMus : public WorkspaceEventHandler {
+ public:
+  WorkspaceEventHandlerMus(ui::Window* workspace_window);
+  ~WorkspaceEventHandlerMus() override;
+
+  // Returns the WorkspaceEventHandlerMus associated with |window|, or null
+  // if |window| is not the workspace window.
+  static WorkspaceEventHandlerMus* Get(ui::Window* window);
+
+  // Returns the window associated with the workspace.
+  ui::Window* workspace_window() { return workspace_window_; }
+
+ private:
+  ui::Window* workspace_window_;
+
+  DISALLOW_COPY_AND_ASSIGN(WorkspaceEventHandlerMus);
+};
+
+}  // namespace mus
+}  // namespace ash
+
+#endif  // ASH_MUS_BRIDGE_WORKSPACE_EVENT_HANDLER_MUS_H_