Use the default theme as the fallback UI in Blink

webkit/glue/webkitplatformsupport_impl.cc

Index: webkit/glue/webkitplatformsupport_impl.cc
diff --git a/webkit/glue/webkitplatformsupport_impl.cc b/webkit/glue/webkitplatformsupport_impl.cc
index 97c59893096c0230e474969e13ebb967151ca224..075c39d9e61236542fdae5b29afb80821b41f2cc 100644
--- a/webkit/glue/webkitplatformsupport_impl.cc
+++ b/webkit/glue/webkitplatformsupport_impl.cc
@@ -63,6 +63,7 @@
 using WebKit::WebAudioBus;
 using WebKit::WebCookie;
 using WebKit::WebData;
+using WebKit::WebFallbackThemeEngine;
 using WebKit::WebLocalizedString;
 using WebKit::WebPluginListBuilder;
 using WebKit::WebString;
@@ -385,7 +386,11 @@ void WebKitPlatformSupportImpl::SetFlingCurveParameters(
 }
 
 WebThemeEngine* WebKitPlatformSupportImpl::themeEngine() {
-  return &theme_engine_;
+  return &native_theme_engine_;
+}
+
+WebFallbackThemeEngine* WebKitPlatformSupportImpl::fallbackThemeEngine() {
+  return &fallback_theme_engine_;
 }
 
 WebURLLoader* WebKitPlatformSupportImpl::createURLLoader() {