Fix "unreachable code" warnings (MSVC warning 4702) in ui/.

ui/gl/gl_implementation_win.cc

 // 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.
 
 #include <vector>
 
 #include "base/at_exit.h"
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 359 matching lines @@
 
 bool GetGLWindowSystemBindingInfo(GLWindowSystemBindingInfo* info) {
   switch (GetGLImplementation()) {
     case kGLImplementationDesktopGL:
       return GetGLWindowSystemBindingInfoWGL(info);
     case kGLImplementationEGLGLES2:
       return GetGLWindowSystemBindingInfoEGL(info);
     default:
       return false;
   }
-  return false;
 }
 
 }  // namespace gfx