Don't supply value for boolean attribute

ui/accelerated_widget_mac/io_surface_context.mm

 // Copyright (c) 2013 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 "ui/accelerated_widget_mac/io_surface_context.h"
 
 #include <OpenGL/gl.h>
 #include <OpenGL/OpenGL.h>
 #include <vector>
 
@@ skipping 17 matching lines @@
     return found->second;
   }
 
   base::ScopedTypeRef<CGLContextObj> cgl_context;
   CGLError error = kCGLNoError;
 
   // Create the pixel format object for the context.
   std::vector<CGLPixelFormatAttribute> attribs;
   attribs.push_back(kCGLPFADepthSize);
   attribs.push_back(static_cast<CGLPixelFormatAttribute>(0));
-  if (ui::GpuSwitchingManager::GetInstance()->SupportsDualGpus()) {
+  if (ui::GpuSwitchingManager::GetInstance()->SupportsDualGpus())
     attribs.push_back(kCGLPFAAllowOfflineRenderers);
-    attribs.push_back(static_cast<CGLPixelFormatAttribute>(1));
-  }
   attribs.push_back(static_cast<CGLPixelFormatAttribute>(0));
   GLint number_virtual_screens = 0;
   base::ScopedTypeRef<CGLPixelFormatObj> pixel_format;
   error = CGLChoosePixelFormat(&attribs.front(),
                                pixel_format.InitializeInto(),
                                &number_virtual_screens);
   if (error != kCGLNoError) {
     LOG(ERROR) << "Failed to create pixel format object.";
     return NULL;
   }
@@ skipping 59 matching lines @@
 IOSurfaceContext::TypeMap*
     IOSurfaceContext::type_map() {
   return type_map_.Pointer();
 }
 
 // static
 base::LazyInstance<IOSurfaceContext::TypeMap>
     IOSurfaceContext::type_map_;
 
 }  // namespace ui