Fix inline focus ring paint invalidation on continuation change

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

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index f416e668c67ffe4f37794a691c548b49dd79aa5d..a5aa20c3bab26ab7af3ac419f99c1a1d231af3d2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -3422,11 +3422,29 @@ inline void LayoutObject::markAncestorsForPaintInvalidation() {
 inline void LayoutObject::setNeedsPaintOffsetAndVisualRectUpdate() {
   if (needsPaintOffsetAndVisualRectUpdate())
     return;
-  m_bitfields.setNeedsPaintOffsetAndVisualRectUpdate(true);
-  for (LayoutObject* parent = paintInvalidationParent();
-       parent && !parent->needsPaintOffsetAndVisualRectUpdate();
-       parent = parent->paintInvalidationParent())
-    parent->m_bitfields.setNeedsPaintOffsetAndVisualRectUpdate(true);
+  for (auto* object = this;
+       object && !object->needsPaintOffsetAndVisualRectUpdate();
+       object = object->paintInvalidationParent()) {

[pdr., 2017/03/21 18:40:49]

Do we need to invalidate both the object and its continuation start? In other
words, could paintInvalidationParent just return the continuation start in this
case?

[Xianzhu, 2017/03/22 02:46:07]

This special case is for focus ring only. Focus ring is the only case that the
visual rect of the start of continuation may depends on continuations. All other
cases just use the normal hierarchy.

+    object->m_bitfields.setNeedsPaintOffsetAndVisualRectUpdate(true);
+
+    // If the object is an anonymous block continuation, mark the start object

[wkorman, 2017/03/21 19:31:52]

Wondered why we only have to mark the start object. Presuming this is an
artifact of how we implement invalidation of continuations, or, the rest of the
continuation will be handled when the other involved objects are invalidated?
Perhaps worth adding to comment.

[Xianzhu, 2017/03/22 02:46:07]

Please see the reply to pdr@'s comment above.

Updated comment to state that this is special case for focus ring only.

+    // of the continuation for paint invalidation if it has focus ring because
+    // change of continuation may change the shape of the focus ring.
+    if (!object->isAnonymous() || !object->isLayoutBlockFlow())
+      continue;
+    auto* blockFlow = toLayoutBlockFlow(object);
+    if (!blockFlow->isAnonymousBlockContinuation())
+      continue;
+
+    if (auto* inlineElementContinuation =
+            blockFlow->inlineElementContinuation()) {
+      auto* startOfContinuations =
+          inlineElementContinuation->node()->layoutObject();
+      if (startOfContinuations &&
+          startOfContinuations->styleRef().outlineStyleIsAuto())
+        startOfContinuations->setMayNeedPaintInvalidation();
+    }
+  }
 }
 
 void LayoutObject::setShouldInvalidateSelection() {