Fix gles2 conformance tests

gpu/gles2_conform_support/native/egl_native_win.cc

 // Copyright (c) 2011 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.
 
 extern "C" {
 #if defined(GLES2_CONFORM_SUPPORT_ONLY)
 #include "gpu/gles2_conform_support/gtf/gtf_stubs.h"
 #else
 #include "third_party/gles2_conform/GTF_ES/glsl/GTF/Source/eglNative.h"
 #endif
@@ skipping 20 matching lines @@
       result = 1;
       break;
     default:
       result = ::DefWindowProc(hwnd, msg, w_param, l_param);
       break;
   }
   return result;
 }
 }  // namespace.
 
+extern "C" {
+
 GTFbool GTFNativeCreateDisplay(EGLNativeDisplayType *pNativeDisplay) {
   *pNativeDisplay = EGL_DEFAULT_DISPLAY;
   return GTFtrue;
 }
 
 void GTFNativeDestroyDisplay(EGLNativeDisplayType nativeDisplay) {
   // Nothing to destroy since we are using EGL_DEFAULT_DISPLAY
 }
 
 GTFbool GTFNativeCreateWindow(EGLNativeDisplayType nativeDisplay,
@@ skipping 53 matching lines @@
   UnregisterClass(kWindowClassName, GetModuleHandle(NULL));
 }
 
 EGLImageKHR GTFCreateEGLImage(int width, int height,
                               GLenum format, GLenum type) {
   return (EGLImageKHR)NULL;
 }
 
 void GTFDestroyEGLImage(EGLImageKHR image) {
 }
+
+}  // extern "C"