MacViews: Fix failing mouse capture unittests.

ui/views/cocoa/cocoa_mouse_capture.h

 // Copyright 2014 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 UI_VIEWS_COCOA_COCOA_MOUSE_CAPTURE_H_
 #define UI_VIEWS_COCOA_COCOA_MOUSE_CAPTURE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "ui/views/views_export.h"
 
+@class NSWindow;
+
 namespace views {
 
 class CocoaMouseCaptureDelegate;
 
 // Basic mouse capture to simulate ::SetCapture() from Windows. This is used to
 // support menu widgets (e.g. on Combo boxes). Clicking anywhere other than the
 // menu should dismiss the menu and "swallow" the mouse event. All events are
 // forwarded, but only events to the same application are "swallowed", which is
 // consistent with how native NSMenus behave.
 class VIEWS_EXPORT CocoaMouseCapture {
  public:
   explicit CocoaMouseCapture(CocoaMouseCaptureDelegate* delegate);
   ~CocoaMouseCapture();
 
+  // Returns the NSWindow with capture or nil if no window has capture
+  // currently.
+  static NSWindow* GetGlobalCaptureWindow();
+
   // True if the event tap is active (i.e. not stolen by a later instance).
   bool IsActive() const { return !!active_handle_; }
 
  private:
   class ActiveEventTap;
 
   // Deactivates the event tap if still active.
   void OnOtherClientGotCapture();
 
   CocoaMouseCaptureDelegate* delegate_;  // Weak. Owns this.
 
   // The active event tap for this capture. Owned by this, but can be cleared
   // out early if another instance of CocoaMouseCapture is created.
   std::unique_ptr<ActiveEventTap> active_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(CocoaMouseCapture);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_COCOA_COCOA_MOUSE_CAPTURE_H_