Unify all types of overflow-related clips for paint and hit testing.

third_party/WebKit/Source/core/layout/LayoutBox.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.cpp b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
index 882eadfab0ba37ccc82799febfbb9f140d5083b5..9989d0d5533f0a1096bf5787f785c8bed6ffdc2b 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -1399,7 +1399,7 @@ bool LayoutBox::nodeAtPoint(HitTestResult& result,
   // TODO(pdr): We should also check for css clip in the !isSelfPaintingLayer
   //            case, similar to overflow clip below.
   bool skipChildren = false;
-  if (hasOverflowClip() && !hasSelfPaintingLayer()) {
+  if (shouldClipOverflow() && !hasSelfPaintingLayer()) {
     if (!locationInContainer.intersects(overflowClipRect(
             adjustedLocation, ExcludeOverlayScrollbarSizeForHitTesting))) {
       skipChildren = true;
@@ -1410,11 +1410,6 @@ bool LayoutBox::nodeAtPoint(HitTestResult& result,
     }
   }
 
-  // A control clip can also clip out child hit testing.
-  if (!skipChildren && hasControlClip() &&
-      !locationInContainer.intersects(controlClipRect(adjustedLocation)))
-    skipChildren = true;
-
   // TODO(pdr): We should also include checks for hit testing border radius at
   //            the layer level (see: crbug.com/568904).
 
@@ -1797,8 +1792,12 @@ LayoutRect LayoutBox::overflowClipRect(
   clipRect.setSize(clipRect.size() - LayoutSize(borderLeft() + borderRight(),
                                                 borderTop() + borderBottom()));
 
+  if (hasControlClip())

[pdr., 2017/01/23 18:46:12]

I think this needs to be after excludeScrollbars.

[chrishtr, 2017/01/23 18:53:20]

DONE!!!

+    clipRect.intersect(controlClipRect(location));
+
   if (hasOverflowClip())
     excludeScrollbars(clipRect, overlayScrollbarClipBehavior);
+
   return clipRect;
 }