Remove windows/mac/ios specific code from //ui

ui/gl/gl_implementation.h

 // 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.
 
 #ifndef UI_GL_GL_IMPLEMENTATION_H_
 #define UI_GL_GL_IMPLEMENTATION_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 19 matching lines @@
 struct GL_EXPORT GLWindowSystemBindingInfo {
   GLWindowSystemBindingInfo();
   std::string vendor;
   std::string version;
   std::string extensions;
   bool direct_rendering;
 };
 
 void GetAllowedGLImplementations(std::vector<GLImplementation>* impls);
 
-#if defined(OS_WIN)
-typedef void* (WINAPI *GLGetProcAddressProc)(const char* name);
-#else
 typedef void* (*GLGetProcAddressProc)(const char* name);
-#endif
 
 // Initialize a particular GL implementation.
 GL_EXPORT bool InitializeStaticGLBindings(GLImplementation implementation);
 
 // Initialize function bindings that depend on the context for a GL
 // implementation.
 GL_EXPORT bool InitializeDynamicGLBindings(GLImplementation implementation,
                                            GLContext* context);
 
 // Initialize Debug logging wrappers for GL bindings.
@@ skipping 54 matching lines @@
 // unsupported.
 void* GetGLProcAddress(const char* name);
 
 // Return information about the GL window system binding implementation (e.g.,
 // EGL, GLX, WGL). Returns true if the information was retrieved successfully.
 GL_EXPORT bool GetGLWindowSystemBindingInfo(GLWindowSystemBindingInfo* info);
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_IMPLEMENTATION_H_