mus: Use the new drag API to implement tab dragging in chrome.

chrome/browser/ui/views/tabs/window_finder_mus.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 CHROME_BROWSER_UI_VIEWS_TABS_WINDOW_FINDER_MUS_H_
+#define CHROME_BROWSER_UI_VIEWS_TABS_WINDOW_FINDER_MUS_H_
+
+#include "chrome/browser/ui/views/tabs/window_finder.h"
+
+class WindowFinderMus : public WindowFinder {
+ public:
+  WindowFinderMus();
+  ~WindowFinderMus() override;
+
+  // Overridden from WindowFinder:
+  gfx::NativeWindow GetLocalProcessWindowAtPoint(
+      const gfx::Point& screen_point,
+      const std::set<gfx::NativeWindow>& ignore) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WindowFinderMus);
+};
+
+#endif  // CHROME_BROWSER_UI_VIEWS_TABS_WINDOW_FINDER_MUS_H_