Fix border radius on composited children.

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 894f7d8e93f14ad42f8ad43f5a2f0513a35b4157..0bd968278c083adb35f933df0839fda7d65ded4a 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -2257,6 +2257,11 @@ bool LayoutBox::paintedOutputOfObjectHasNoEffectRegardlessOfSize() const {
       return false;
   }
 
+  // If the box paints into its own backing, we can assume that it's painting
+  // must have some effect.

[chrishtr, 2016/12/12 19:41:46]

s/can/must/. Also mention one such case, which is applying a clip inherited from
an ancestor.

[Stephen Chennney, 2016/12/12 19:49:47]

Done.

+  if (hasLayer() && layer()->compositingState() == PaintsIntoOwnBacking)
+    return false;
+
   return true;
 }