Early out if the scroll position passed in by js is NaN

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 643 matching lines @@
 
         if (FrameView* view = document().view()) {
             if (RenderView* renderView = document().renderView())
                 return adjustScrollForAbsoluteZoom(view->scrollY(), *renderView);
         }
     }
 
     return 0;
 }
 
 void Element::setScrollLeft(double newLeft)

[Rick Byers, 2014/10/22 13:55:33]

Sorry, should have mentioned this earlier: setScrollLeft/setScrollTop are
overridden by HTMLBodyElement - for consistency you should have the same logic
there (hopefully we can eventually simplify all this when
RuntimeEnabledFeatures::scrollTopLeftInterop is the default).

[Yufeng Shen (Slow to review), 2014/10/22 17:38:46]

Done.

 {
     document().updateLayoutIgnorePendingStylesheets();
 
+    if (std::isnan(newLeft))
+        return;
+
     if (document().documentElement() != this) {
         RenderBox* rend = renderBox();
-        if (rend && !std::isnan(newLeft))
+        if (rend)
             rend->setScrollLeft(LayoutUnit::fromFloatRound(newLeft * rend->style()->effectiveZoom()));
         return;
     }
 
     if (RuntimeEnabledFeatures::scrollTopLeftInteropEnabled()) {
         if (document().inQuirksMode())
             return;
 
         LocalFrame* frame = document().frame();
         if (!frame)
@@ skipping 24 matching lines @@
     }
 
     // FIXME: Use scrollBehavior to decide whether to scroll smoothly or instantly.
     setScrollLeft(position);
 }
 
 void Element::setScrollTop(double newTop)
 {
     document().updateLayoutIgnorePendingStylesheets();
 
+    if (std::isnan(newTop))
+        return;
+
     if (document().documentElement() != this) {
         RenderBox* rend = renderBox();
-        if (rend && !std::isnan(newTop))
+        if (rend)
             rend->setScrollTop(LayoutUnit::fromFloatRound(newTop * rend->style()->effectiveZoom()));
         return;
     }
 
     if (RuntimeEnabledFeatures::scrollTopLeftInteropEnabled()) {
         if (document().inQuirksMode())
             return;
 
         LocalFrame* frame = document().frame();
         if (!frame)
@@ skipping 2580 matching lines @@
         return wrapper;
 
     CustomElementBinding* binding = perContextData->customElementBinding(customElementDefinition());
 
     wrapper->SetPrototype(binding->prototype());
 
     return V8DOMWrapper::associateObjectWithWrapperNonTemplate(this, wrapperType, wrapper, isolate);
 }
 
 } // namespace blink