Fix processing of mouse events on MacViews.

ui/base/cocoa/base_view.h

 // Copyright (c) 2012 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_BASE_COCOA_BASE_VIEW_H_
 #define UI_BASE_COCOA_BASE_VIEW_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_nsobject.h"
@@ skipping 18 matching lines @@
   ui::ScopedCrTrackingArea trackingArea_;
   BOOL dragging_;
   base::scoped_nsobject<NSEvent> pendingExitEvent_;
   NSInteger pressureEventStage_;
 }
 
 // Override these methods (mouseEvent, keyEvent, forceTouchEvent) in a
 // subclass.
 - (void)mouseEvent:(NSEvent *)theEvent;
 
+// Passes the event to the view's superview, so it could be processed there.
+- (void)passMouseEventToSuperview:(NSEvent*)theEvent;
+
 // keyEvent should return kEventHandled if it handled the event, or
 // kEventNotHandled if it should be forwarded to BaseView's super class.
 - (EventHandled)keyEvent:(NSEvent *)theEvent;
 
 - (void)forceTouchEvent:(NSEvent*)theEvent;
 
 // Useful rect conversions (doing coordinate flipping)
 - (gfx::Rect)flipNSRectToRect:(NSRect)rect;
 - (NSRect)flipRectToNSRect:(gfx::Rect)rect;
 
 @end
 
 // A notification that a view may issue when it receives first responder status.
 // The name is |kViewDidBecomeFirstResponder|, the object is the view, and the
 // NSSelectionDirection is wrapped in an NSNumber under the key
 // |kSelectionDirection|.
 UI_BASE_EXPORT extern NSString* kViewDidBecomeFirstResponder;
 UI_BASE_EXPORT extern NSString* kSelectionDirection;
 
 #endif  // UI_BASE_COCOA_BASE_VIEW_H_