Fix link's hover state if the link under scrollbar

third_party/WebKit/Source/core/page/ChromeClient.cpp

 /*
  * Copyright (C) 2006, 2007, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2012, Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 133 matching lines @@
     return false;
   return openJavaScriptDialog(frame, prompt, ChromeClient::PromptDialog,
                               [this, frame, &prompt, &defaultValue, &result]() {
                                 return openJavaScriptPromptDelegate(
                                     frame, prompt, defaultValue, result);
                               });
 }
 
 void ChromeClient::mouseDidMoveOverElement(LocalFrame& frame,
                                            const HitTestResult& result) {
-  if (result.innerNode() &&
+  if (!result.scrollbar() && result.innerNode() &&
       result.innerNode()->document().isDNSPrefetchEnabled())
     prefetchDNS(result.absoluteLinkURL().host());
 
   showMouseOverURL(result);
 
-  setToolTip(frame, result);
+  if (result.scrollbar())
+    clearToolTip(frame);
+  else
+    setToolTip(frame, result);
 }
 
 void ChromeClient::setToolTip(LocalFrame& frame, const HitTestResult& result) {
   // First priority is a tooltip for element with "title" attribute.
   TextDirection toolTipDirection;
   String toolTip = result.title(toolTipDirection);
 
   // Lastly, some elements provide default tooltip strings.  e.g. <input
   // type="file" multiple> shows a tooltip for the selected filenames.
   if (toolTip.isEmpty()) {
@@ skipping 38 matching lines @@
   // Defer loads in case the client method runs a new event loop that would
   // otherwise cause the load to continue while we're in the middle of
   // executing JavaScript.
   ScopedPageLoadDeferrer deferrer;
 
   printDelegate(frame);
   return true;
 }
 
 }  // namespace blink