Split NativeThemeAura into Overlay and NonOverlay versions.

third_party/WebKit/Source/web/WebRuntimeFeatures.cpp

Index: third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
diff --git a/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp b/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
index 7210346101444dc13b417f037415aa209cc9d000..66ae73dadde68e1d65de7fdaec9856e8ca5df158 100644
--- a/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
+++ b/third_party/WebKit/Source/web/WebRuntimeFeatures.cpp
@@ -182,6 +182,14 @@ bool WebRuntimeFeatures::isOriginTrialsEnabled() {
   return RuntimeEnabledFeatures::originTrialsEnabled();
 }
 
+void WebRuntimeFeatures::enableOverlayScrollbars(bool enable) {
+  RuntimeEnabledFeatures::setOverlayScrollbarsEnabled(enable);
+}
+
+bool WebRuntimeFeatures::isOverlayScrollbarsEnabled() {
+  return RuntimeEnabledFeatures::overlayScrollbarsEnabled();
+}
+
 void WebRuntimeFeatures::enablePagePopup(bool enable) {
   RuntimeEnabledFeatures::setPagePopupEnabled(enable);
 }
@@ -246,10 +254,6 @@ void WebRuntimeFeatures::enableXSLT(bool enable) {
   RuntimeEnabledFeatures::setXSLTEnabled(enable);
 }
 
-void WebRuntimeFeatures::enableOverlayScrollbars(bool enable) {
-  RuntimeEnabledFeatures::setOverlayScrollbarsEnabled(enable);
-}
-
 void WebRuntimeFeatures::forceOverlayFullscreenVideo(bool enable) {
   RuntimeEnabledFeatures::setForceOverlayFullscreenVideoEnabled(enable);
 }