Revert of Implement overlay scrollbar fade out for non-composited scrollers.

third_party/WebKit/public/platform/WebThemeEngine.h

Index: third_party/WebKit/public/platform/WebThemeEngine.h
diff --git a/third_party/WebKit/public/platform/WebThemeEngine.h b/third_party/WebKit/public/platform/WebThemeEngine.h
index b14ccc03c36eaf62bb13084fef8dd54acc7dd4d0..8fe876d11d9b8f6647bde8d53955354c46014e4d 100644
--- a/third_party/WebKit/public/platform/WebThemeEngine.h
+++ b/third_party/WebKit/public/platform/WebThemeEngine.h
@@ -163,11 +163,9 @@
     int thumbThickness;
     int scrollbarMargin;
     WebColor color;
-    double fadeOutDelaySeconds;
-    double fadeOutDurationSeconds;
   };
 
-  // Gets the overlay scrollbar style. Not used on Mac.
+  // Gets the overlay scrollbar style. Used for mobile theme.
   virtual void getOverlayScrollbarStyle(ScrollbarStyle*) {}
 
   // Paint the given the given theme part.