Eliminate drag-off-end scroll canceling for Linux.

content/renderer/webscrollbarbehavior_impl_gtkoraura.cc

Index: content/renderer/webscrollbarbehavior_impl_gtkoraura.cc
diff --git a/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc b/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc
index e9d77bb3f50c81192d3d75e843ca5525c3c4fbb5..b866e29138fc2cc096147b072b3ea896516d19f3 100644
--- a/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc
+++ b/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc
@@ -40,8 +40,16 @@ bool WebScrollbarBehaviorImpl::shouldSnapBackToDragOrigin(
       (isHorizontal ? kOffEndMultiplier : kOffSideMultiplier) * -thickness,
       (isHorizontal ? kOffSideMultiplier : kOffEndMultiplier) * -thickness);
 
-  // We should snap iff the event is outside our calculated rect.
+  // On most platforms, we should snap iff the event is outside our calculated
+  // rect.  On Linux, however, we should not snap for events off the ends, but
+  // not the sides, of the rect.
+#if (defined(OS_LINUX) && !defined(OS_CHROMEOS))
+  return isHorizontal ?
+      (eventPoint.y < noSnapRect.y() || eventPoint.y >= noSnapRect.bottom()) :
+      (eventPoint.x < noSnapRect.x() || eventPoint.x >= noSnapRect.right());
+#else
   return !noSnapRect.Contains(eventPoint);
+#endif
 }
 
 }  // namespace content