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

third_party/WebKit/Source/core/paint/PaintLayer.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index 62a1ce16e876f295d51ecba6a033efc97d0e7185..51ecd0567278cc834b40025311ca8c39bbb999cf 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -49,6 +49,7 @@
 #include "core/css/PseudoStyleRequest.h"
 #include "core/dom/Document.h"
 #include "core/dom/shadow/ShadowRoot.h"
+#include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
@@ -70,6 +71,7 @@
 #include "core/page/Page.h"
 #include "core/page/scrolling/RootScrollerController.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
+#include "core/page/scrolling/TopDocumentRootScrollerController.h"
 #include "core/paint/BoxReflectionUtils.h"
 #include "core/paint/FilterEffectBuilder.h"
 #include "core/paint/ObjectPaintInvalidator.h"
@@ -212,6 +214,14 @@ LayoutRect PaintLayer::visualRect() const {
   return m_layoutObject->visualRect();
 }
 
+bool PaintLayer::isRootScrollerLayer() const {
+  return this ==
+         layoutObject()
+             ->document()
+             .rootScrollerController()
+             .rootScrollerPaintLayer();
+}
+
 PaintLayerCompositor* PaintLayer::compositor() const {
   if (!layoutObject()->view())
     return 0;
@@ -1700,12 +1710,27 @@ void PaintLayer::collectFragments(
   }
 }
 
-static inline LayoutRect frameVisibleRect(LayoutObject* layoutObject) {
-  FrameView* frameView = layoutObject->document().view();
+static inline LayoutRect frameVisibleRect(PaintLayer* layer) {
+  LayoutObject* layoutObject = layer->layoutObject();
+  DCHECK(layoutObject);
+
+  Document& doc = layoutObject->document();
+
+  FrameView* frameView = doc.view();
   if (!frameView)
     return LayoutRect();
 
-  return LayoutRect(frameView->visibleContentRect());
+  IntRect frameRect = frameView->visibleContentRect(ExcludeScrollbars);
+
+  FrameHost* host = doc.frameHost();
+  DCHECK(host);
+  if (host->globalRootScrollerController().isRootScrollerAncestor(doc)) {

[chrishtr, 2017/01/21 02:06:47]

This adjustment in hit-testing code doesn't also appear in in LayoutBox.
Why not?

+    frameRect.setSize(host->globalRootScrollerController()
+                          .visibleContentRect(ExcludeScrollbars)
+                          .size());
+  }
+
+  return LayoutRect(frameRect);
 }
 
 bool PaintLayer::hitTest(HitTestResult& result) {
@@ -1719,7 +1744,7 @@ bool PaintLayer::hitTest(HitTestResult& result) {
   const HitTestLocation& hitTestLocation = result.hitTestLocation();
 
   // Start with frameVisibleRect to ensure we include the scrollbars.
-  LayoutRect hitTestArea = frameVisibleRect(layoutObject());
+  LayoutRect hitTestArea = frameVisibleRect(this);
   if (request.ignoreClipping())
     hitTestArea.unite(LayoutRect(layoutObject()->view()->documentRect()));