Converts BaseView to be non-opaque, which will fix drawing of...

chrome/browser/cocoa/base_view.mm

 // Copyright (c) 2009 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.
 
 #include "chrome/browser/cocoa/base_view.h"
 
 @implementation BaseView
 
 - (id)initWithFrame:(NSRect)frame {
   self = [super initWithFrame:frame];
@@ skipping 74 matching lines @@
 }
 
 - (void)keyDown:(NSEvent *)theEvent {
   [self keyEvent:theEvent];
 }
 
 - (void)keyUp:(NSEvent *)theEvent {
   [self keyEvent:theEvent];
 }
 
-- (BOOL)isOpaque {
-  return YES;
-}
-
 - (gfx::Rect)NSRectToRect:(NSRect)rect {
   gfx::Rect new_rect(NSRectToCGRect(rect));
   new_rect.set_y([self bounds].size.height - new_rect.y() - new_rect.height());
   return new_rect;
 }
 
 - (NSRect)RectToNSRect:(gfx::Rect)rect {
   NSRect new_rect(NSRectFromCGRect(rect.ToCGRect()));
   new_rect.origin.y =
       [self bounds].size.height - new_rect.origin.y - new_rect.size.height;
   return new_rect;
 }
 
 @end