Fix collapsed-border painting for layered table and cells

third_party/WebKit/Source/core/paint/PaintInvalidator.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/paint/PaintInvalidator.h"
 
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
@@ skipping 196 matching lines @@
   } else if (object.isColumnSpanAll() ||
              object.isFloatingWithNonContainingBlockParent()) {
     // See LayoutObject::paintingLayer() for the special-cases of floating under
     // inline and multicolumn.
     context.paintingLayer = object.paintingLayer();
   }
 
   if (object.isLayoutBlockFlow() && toLayoutBlockFlow(object).containsFloats())
     context.paintingLayer->setNeedsPaintPhaseFloat();
 
-  if (&object == &context.paintingLayer->layoutObject())
+  // Table collapsed borders are painted in PaintPhaseDescendantBlockBackgrounds
+  // on the table's layer.
+  if (object.isTable()) {
+    const LayoutTable& table = toLayoutTable(object);
+    if (table.collapseBorders() && !table.collapsedBorders().isEmpty())
+      context.paintingLayer->setNeedsPaintPhaseDescendantBlockBackgrounds();

[wkorman, 2017/02/27 19:46:23]

LayoutTable::invalidatePaintIfNeeded already does this, is that not called when
spinvalidation is enabled, or does this cover another case?

[Xianzhu, 2017/02/27 20:22:49]

LayoutTable::invalidatePaintIfNeeded(PaintInvalidationState) is the
non-spinvalidation path.

+  }
+
+  // The following flags are for descendants of the layer object only.
+  if (object == context.paintingLayer->layoutObject())

[wkorman, 2017/02/27 19:46:23]

Why change from pointer to operator==? Are there perf ramifications?

[Xianzhu, 2017/02/27 20:22:49]

They are the same in binary code, but omitting '&' shortens the source code and
avoids potential errors of comparing address of pointers (e.g. in case that
'object' is changed to a pointer for some reason).

We use references and pointers to LayoutObjects interchangeably in comparison.
See
https://groups.google.com/a/chromium.org/forum/#!searchin/blink-dev/Why$20we$...
for discussion.

     return;
 
   if (object.styleRef().hasOutline())
     context.paintingLayer->setNeedsPaintPhaseDescendantOutlines();
 
   if (object.hasBoxDecorationBackground()
       // We also paint overflow controls in background phase.
       || (object.hasOverflowClip() &&
           toLayoutBox(object).getScrollableArea()->hasOverflowControls())) {
     context.paintingLayer->setNeedsPaintPhaseDescendantBlockBackgrounds();
   }
-
-  if (object.isTable()) {
-    const LayoutTable& table = toLayoutTable(object);
-    if (table.collapseBorders() && !table.collapsedBorders().isEmpty())
-      context.paintingLayer->setNeedsPaintPhaseDescendantBlockBackgrounds();
-  }
 }
 
 namespace {
 
 // This is temporary to workaround paint invalidation issues in
 // non-rootLayerScrolls mode.
 // It undoes FrameView's content clip and scroll for paint invalidation of frame
 // scroll controls and the LayoutView to which the content clip and scroll don't
 // apply.
 class ScopedUndoFrameViewContentClipAndScroll {
@@ skipping 219 matching lines @@
         PaintInvalidatorContext::ForcedSubtreeInvalidationRectUpdate;
 }
 
 void PaintInvalidator::processPendingDelayedPaintInvalidations() {
   for (auto target : m_pendingDelayedPaintInvalidations)
     target->getMutableForPainting().setShouldDoFullPaintInvalidation(
         PaintInvalidationDelayedFull);
 }
 
 }  // namespace blink