Fix wheel scrolling over scrollbar not scrolling page.

third_party/WebKit/Source/core/input/EventHandler.cpp

Index: third_party/WebKit/Source/core/input/EventHandler.cpp
diff --git a/third_party/WebKit/Source/core/input/EventHandler.cpp b/third_party/WebKit/Source/core/input/EventHandler.cpp
index 645d51be8477559971abd6939f700eb84dfff90a..3931b98fea8f8b8daeb2f8a700da9927d97d1f2b 100644
--- a/third_party/WebKit/Source/core/input/EventHandler.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandler.cpp
@@ -1798,6 +1798,10 @@ WebInputEventResult EventHandler::handleWheelEvent(const PlatformWheelEvent& eve
     if (node && node->isTextNode())
         node = FlatTreeTraversal::parent(*node);
 
+    // If we're over the frame scrollbar, scroll the document.
+    if (!node && result.scrollbar())
+        node = doc->documentElement();
+
     bool sendDOMEvent = true;
     LocalFrame* subframe = subframeForTargetNode(node);
     if (subframe) {