chrome/browser should build on the x86_64 architecture

chrome/browser/ui/cocoa/notifications/balloon_view.mm

 // Copyright (c) 2011 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/ui/cocoa/notifications/balloon_view.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_nsobject.h"
 #import "chrome/browser/ui/cocoa/notifications/balloon_controller.h"
 #import "third_party/GTM/AppKit/GTMNSBezierPath+RoundRect.h"
 
 namespace {
 
 const int kRoundedCornerSize = 6;
 
 }  // namespace
 
 @implementation BalloonWindow
 - (id)initWithContentRect:(NSRect)contentRect
-                styleMask:(unsigned int)aStyle
+                styleMask:(NSUInteger)aStyle
                   backing:(NSBackingStoreType)bufferingType
                     defer:(BOOL)flag {
   self = [super initWithContentRect:contentRect
                           styleMask:NSBorderlessWindowMask
                             backing:NSBackingStoreBuffered
                               defer:NO];
   // Using NSModalPanelWindowLevel (8) rather then NSStatusWindowLevel (25)
   // ensures notification balloons on top of regular windows, but below
   // popup menus which are at NSPopUpMenuWindowLevel (101) and Spotlight
   // drop-out, which is at NSStatusWindowLevel-2 (23) for OSX 10.6/7.
@@ skipping 59 matching lines @@
 - (void)mouseDown:(NSEvent*)event {
   [NSApp preventWindowOrdering];
   // Continue bubbling the event up the chain of responders.
   [super mouseDown:event];
 }
 
 - (BOOL)acceptsFirstMouse:(NSEvent*)event {
   return YES;
 }
 @end