Fix gles2 conformance tests

gpu/gles2_conform_support/native/egl_native_win.cc

Index: gpu/gles2_conform_support/native/egl_native_win.cc
diff --git a/gpu/gles2_conform_support/native/egl_native_win.cc b/gpu/gles2_conform_support/native/egl_native_win.cc
index c083cca26cdf8a0ce9b108b3c89d7103c9a780d3..4026966ed831aa7e4ef4adde5b79f8bb784344f0 100644
--- a/gpu/gles2_conform_support/native/egl_native_win.cc
+++ b/gpu/gles2_conform_support/native/egl_native_win.cc
@@ -38,6 +38,8 @@ LRESULT CALLBACK WindowProc(HWND hwnd, UINT msg,
 }
 }  // namespace.
 
+extern "C" {
+
 GTFbool GTFNativeCreateDisplay(EGLNativeDisplayType *pNativeDisplay) {
   *pNativeDisplay = EGL_DEFAULT_DISPLAY;
   return GTFtrue;
@@ -111,3 +113,5 @@ EGLImageKHR GTFCreateEGLImage(int width, int height,
 
 void GTFDestroyEGLImage(EGLImageKHR image) {
 }
+
+}  // extern "C"