Fix event passing to overlay scrollbars when over a plugin

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 311c08d979be7bfe6eaa96f14f6b796ca4f11592..8526eb9529d6af53799b38102e01f07fdbf0ed3f 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -491,8 +491,8 @@ void WebViewImpl::handleMouseDown(LocalFrame& mainFrame, const WebMouseEvent& ev
 
     m_lastMouseDownPoint = WebPoint(event.x, event.y);
 
-    if (event.button == WebMouseEvent::ButtonLeft) {
-        IntPoint point(event.x, event.y);
+    IntPoint point(event.x, event.y);
+    if (event.button == WebMouseEvent::ButtonLeft && !m_page->mainFrame()->view()->scrollbarAtPoint(point)) {

[Rick Byers, 2014/05/22 13:53:36]

Again, why isn't the problem here really that the hit test below is broken?  If
the hit test properly hit the scrollbar then I think we wouldn't need this hack.

         point = m_page->mainFrame()->view()->windowToContents(point);
         HitTestResult result(m_page->mainFrame()->eventHandler().hitTestResultAtPoint(point));
         Node* hitNode = result.innerNonSharedNode();