Expand PaintLayer clip to account for hidden URL bar with document.rootScroller

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/input/EventHandlingUtil.h"
 
+#include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/layout/api/LayoutViewItem.h"
+#include "core/page/scrolling/TopDocumentRootScrollerController.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/scroll/ScrollableArea.h"
 
 namespace blink {
 namespace EventHandlingUtil {
 
 HitTestResult hitTestResultInFrame(LocalFrame* frame,
                                    const LayoutPoint& point,
                                    HitTestRequest::HitTestRequestType hitType) {
   HitTestResult result(HitTestRequest(hitType), point);
 
-  if (!frame || frame->contentLayoutItem().isNull())
+  if (!frame || frame->contentLayoutItem().isNull() || !frame->view())
     return result;
-  if (frame->view()) {
-    IntRect rect = frame->view()->visibleContentRect(IncludeScrollbars);
-    if (!rect.contains(roundedIntPoint(point)))
-      return result;
+
+  IntRect frameRect = frame->view()->visibleContentRect(IncludeScrollbars);
+
+  DCHECK(frame->host());
+  DCHECK(frame->document());
+  TopDocumentRootScrollerController& rootScrollerController =
+      frame->host()->globalRootScrollerController();
+  if (rootScrollerController.isRootScrollerAncestor(*frame->document())) {
+    frameRect.setSize(
+        rootScrollerController.visibleContentRect(IncludeScrollbars).size());
   }
+
+  if (!frameRect.contains(roundedIntPoint(point)))
+    return result;
+
   frame->contentLayoutItem().hitTest(result);
   return result;
 }
 
 WebInputEventResult mergeEventResult(WebInputEventResult resultA,
                                      WebInputEventResult resultB) {
   // The ordering of the enumeration is specific. There are times that
   // multiple events fire and we need to combine them into a single
   // result code. The enumeration is based on the level of consumption that
   // is most significant. The enumeration is ordered with smaller specified
@@ skipping 75 matching lines @@
     const PlatformMouseEvent& mev) {
   DCHECK(frame);
   DCHECK(frame->document());
 
   return frame->document()->performMouseEventHitTest(
       request, contentPointFromRootFrame(frame, mev.position()), mev);
 }
 
 }  // namespace EventHandlingUtil
 }  // namespace blink