chrome/browser should build on the x86_64 architecture

chrome/browser/ui/cocoa/extensions/browser_actions_controller.mm

 // 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.
 
 #import "browser_actions_controller.h"
 
 #include <cmath>
 #include <string>
 
 #include "base/sys_string_conversions.h"
@@ skipping 570 matching lines @@
   for (BrowserActionButton* button in [buttons_ allValues]) {
     NSRect buttonFrame = [button frame];
     if (NSContainsRect([containerView_ bounds], buttonFrame)) {
       if ([button alphaValue] != 1.0)
         [button setAlphaValue:1.0];
 
       continue;
     }
     CGFloat intersectionWidth =
         NSWidth(NSIntersectionRect([containerView_ bounds], buttonFrame));
-    CGFloat alpha = std::max(0.0f, intersectionWidth / NSWidth(buttonFrame));
+    CGFloat alpha = std::max(static_cast<CGFloat>(0.0),
+                             intersectionWidth / NSWidth(buttonFrame));
     [button setAlphaValue:alpha];
     [button setNeedsDisplay:YES];
   }
 }
 
 - (BrowserActionButton*)buttonForExtension:(const Extension*)extension {
   NSString* extensionId = base::SysUTF8ToNSString(extension->id());
   DCHECK(extensionId);
   if (!extensionId)
     return nil;
@@ skipping 260 matching lines @@
   const extensions::ExtensionList& toolbar_items =
       toolbarModel_->toolbar_items();
   if (index < toolbar_items.size()) {
     const Extension* extension = toolbar_items[index];
     return [buttons_ objectForKey:base::SysUTF8ToNSString(extension->id())];
   }
   return nil;
 }
 
 @end