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

ui/gl/gl_bindings.cc

 // Copyright 2014 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.
 
-#if defined(OS_WIN) || defined(USE_X11) || defined(OS_ANDROID) || defined(USE_OZONE)
+#if defined(USE_X11) || defined(OS_ANDROID) || defined(USE_OZONE)
 #include <EGL/egl.h>
 #endif
 
 #include "ui/gl/gl_bindings.h"
 
 #if defined(USE_X11)
 #include "ui/gfx/x/x11_types.h"
 #endif
 
-#if defined(OS_WIN)
-#include "ui/gl/gl_surface_wgl.h"
-#endif
-
-#if defined(OS_WIN) || defined(USE_X11) || defined(OS_ANDROID) || defined(USE_OZONE)
+#if defined(USE_X11) || defined(OS_ANDROID) || defined(USE_OZONE)
 #include "ui/gl/gl_surface_egl.h"
 #endif
 
 namespace gfx {
 
 std::string DriverOSMESA::GetPlatformExtensions() {
   return "";
 }
 
-#if defined(OS_WIN)
-std::string DriverWGL::GetPlatformExtensions() {
-  const char* str = nullptr;
-  if (g_driver_wgl.fn.wglGetExtensionsStringARBFn) {
-    str = g_driver_wgl.fn.wglGetExtensionsStringARBFn(
-        GLSurfaceWGL::GetDisplayDC());
-  } else if (g_driver_wgl.fn.wglGetExtensionsStringEXTFn) {
-    str = g_driver_wgl.fn.wglGetExtensionsStringEXTFn();
-  }
-  return str ? std::string(str) : "";
-}
-#endif
-
-#if defined(OS_WIN) || defined(USE_X11) || defined(OS_ANDROID) || defined(USE_OZONE)
+#if defined(USE_X11) || defined(OS_ANDROID) || defined(USE_OZONE)
 std::string DriverEGL::GetPlatformExtensions() {
   EGLDisplay display =
-#if defined(OS_WIN)
-    GLSurfaceEGL::GetPlatformDisplay(GetPlatformDefaultEGLNativeDisplay());
-#else
     g_driver_egl.fn.eglGetDisplayFn(GetPlatformDefaultEGLNativeDisplay());
-#endif
 
   DCHECK(g_driver_egl.fn.eglInitializeFn);
   g_driver_egl.fn.eglInitializeFn(display, NULL, NULL);
   DCHECK(g_driver_egl.fn.eglQueryStringFn);
   const char* str = g_driver_egl.fn.eglQueryStringFn(display, EGL_EXTENSIONS);
   return str ? std::string(str) : "";
 }
 #endif
 
 #if defined(USE_X11)
 std::string DriverGLX::GetPlatformExtensions() {
   DCHECK(g_driver_glx.fn.glXQueryExtensionsStringFn);
   const char* str =
       g_driver_glx.fn.glXQueryExtensionsStringFn(gfx::GetXDisplay(), 0);
   return str ? std::string(str) : "";
 }
 #endif
 
 }  // namespace gfx