Refactor LayoutInline::addOutlineRects to avoid tricky logic to avoid dups

Source/core/layout/LayoutBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 2579 matching lines @@
                 rects.append(rect);
         }
 
         addOutlineRectsForNormalChildren(rects, additionalOffset);
         if (TrackedLayoutBoxListHashSet* positionedObjects = this->positionedObjects()) {
             for (auto* box : *positionedObjects)
                 addOutlineRectsForDescendant(*box, rects, additionalOffset);
         }
     }
 
-    if (inlineElementContinuation) {
-        Vector<LayoutRect> inlineOutlineRects;
-        // We need to give the LayoutInline a clean vector to let it add focus ring rects of line boxes.
-        inlineElementContinuation->addOutlineRects(inlineOutlineRects, additionalOffset + (inlineElementContinuation->containingBlock()->location() - location()));
-        rects.appendVector(inlineOutlineRects);
-    }
+    if (inlineElementContinuation)

[chrishtr, 2015/08/07 23:35:31]

Can this code just be deleted, and then the special casing in
LayoutBoxModelObject::addOutlineRectsForDescendant is gone?

[Xianzhu, 2015/08/07 23:56:23]

They are for different cases. You can treat the addOutlineRects a
two-dimensional action:
- parent-children dimension
- and continuation dimension.

The code path (and special case) in
LayoutBoxModelObject::addOutlineRectsForDescendant() is in parent-children
dimension, where we don't want descendant LayoutInline to add duplicated line
boxes.

This 'inlineElementContinuation' code is executed in continuation dimension as
  LayoutInline::addOutlineRects()
 -> (same 'this') LayoutInline::addOutlineRectsForChildrenAndContinuation()
 -> (block continuation) LayoutBlock::addOutlineRects()
 -> (inline continuation) LayoutInline::addOutlineRects()
Here the last LayoutInline is not a descendant of any previous objects which
have added outline rects, so we call addOutlineRects() to let it add all outline
rects of it.

[chrishtr, 2015/08/08 02:42:00]

Then I don't understand where the potential duplication of outline rects is
coming from. I thought this was the place where outline rects were being
generated that duplicated things and necessitated the special case in
LayoutBoxModelObject::addOutlineRectsForDescendant(). I guess not? Where do the
duplicates come from?

+        inlineElementContinuation->addOutlineRects(rects, additionalOffset + (inlineElementContinuation->containingBlock()->location() - location()));
 }
 
 void LayoutBlock::computeSelfHitTestRects(Vector<LayoutRect>& rects, const LayoutPoint& layerOffset) const
 {
     LayoutBox::computeSelfHitTestRects(rects, layerOffset);
 
     if (hasHorizontalLayoutOverflow() || hasVerticalLayoutOverflow()) {
         for (RootInlineBox* curr = firstRootBox(); curr; curr = curr->nextRootBox()) {
             LayoutUnit top = std::max<LayoutUnit>(curr->lineTop(), curr->top());
             LayoutUnit bottom = std::min<LayoutUnit>(curr->lineBottom(), curr->top() + curr->height());
@@ skipping 309 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink