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

Source/core/frame/LocalDOMWindow.cpp

Index: Source/core/frame/LocalDOMWindow.cpp
diff --git a/Source/core/frame/LocalDOMWindow.cpp b/Source/core/frame/LocalDOMWindow.cpp
index e347ad1045eab396af17f553cea46caed05003b3..1413db1de2b3e796cd65d0ceda7bada5f12a9940 100644
--- a/Source/core/frame/LocalDOMWindow.cpp
+++ b/Source/core/frame/LocalDOMWindow.cpp
@@ -1403,6 +1403,12 @@ void LocalDOMWindow::scrollTo(double x, double y, ScrollBehavior scrollBehavior)
     if (!view)
         return;
 
+    // If the scrollTo position x/y is NaN, explicitly set it to 0.
+    if (x != x)

[Rick Byers, 2014/10/21 20:44:15]

use std::isnan (then you can also remove the comment which will be redundant
with the code).

+        x = 0;
+    if (y != y)
+        y = 0;
+
     DoublePoint layoutPos(x * m_frame->pageZoomFactor(), y * m_frame->pageZoomFactor());
     view->setScrollPosition(layoutPos, scrollBehavior);
 }