Fix the inconsistent problem while the content of textNodes is changed

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

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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 16 matching lines @@
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/Text.h"
 #include "core/editing/VisiblePosition.h"
 #include "core/editing/iterators/TextIterator.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutTableCell.h"
 #include "core/layout/LayoutTextCombine.h"
 #include "core/layout/LayoutView.h"
+#include "core/layout/TextAutosizer.h"
 #include "core/layout/api/LineLayoutBox.h"
 #include "core/layout/line/AbstractInlineTextBox.h"
 #include "core/layout/line/EllipsisBox.h"
 #include "core/layout/line/GlyphOverflow.h"
 #include "core/layout/line/InlineTextBox.h"
 #include "platform/fonts/CharacterRange.h"
 #include "platform/geometry/FloatQuad.h"
 #include "platform/text/BidiResolver.h"
 #include "platform/text/Character.h"
 #include "platform/text/Hyphenation.h"
@@ skipping 155 matching lines @@
   const ComputedStyle& newStyle = styleRef();
   ETextTransform oldTransform = oldStyle ? oldStyle->textTransform() : TTNONE;
   ETextSecurity oldSecurity = oldStyle ? oldStyle->textSecurity() : TSNONE;
   if (oldTransform != newStyle.textTransform() ||
       oldSecurity != newStyle.textSecurity())
     transformText();
 
   // This is an optimization that kicks off font load before layout.
   if (!text().containsOnlyWhitespace())
     newStyle.font().willUseFontData(text());
+
+  TextAutosizer* textAutosizer = document().textAutosizer();
+  if (!oldStyle && textAutosizer)

[pdr., 2016/11/20 06:38:13]

This approach of calling newNodeAdded for each node could be a little slow
because each node independently finds the nearest cluster. I wonder if we could
simplify this by tracking a set of blocks in the autosizer
(HashSet<LayoutBlock*> m_blocksWithNewText), and adding the nearest block for
each text node? In prepareForLayout, we could then do the expensive
nearest-cluster lookup for each of the blocks.

[cathiechentx, 2016/11/22 08:14:47]

Actually this approach isn't as slow as it looks like. It will find the
nearest-clusters for all new nodes(block nodes and text nodes). So if a node's
parent is new(!everHadLayout()), there's no need for this node to travel up the
tree to find nearest-cluster, cause its parent already found it and added it to
the hashset.

If we add a subtree to the dom tree, the costs are: the root of subtree finding
nearest-cluster, adding it to hashset and all descendants checking if parent are
new.

+    textAutosizer->newNodeAdded(this);
 }
 
 void LayoutText::removeAndDestroyTextBoxes() {
   if (!documentBeingDestroyed()) {
     if (firstTextBox()) {
       if (isBR()) {
         RootInlineBox* next = firstTextBox()->root().nextRootBox();
         if (next)
           next->markDirty();
       }
@@ skipping 1437 matching lines @@
   // LayoutObjectChildList::insertChildNode() fails to set true to owner.
   // To avoid that, we call setNeedsLayoutAndPrefWidthsRecalc() only if this
   // LayoutText has parent.
   if (parent())
     setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(
         LayoutInvalidationReason::TextChanged);
   m_knownToHaveNoOverflowAndNoFallbackFonts = false;
 
   if (AXObjectCache* cache = document().existingAXObjectCache())
     cache->textChanged(this);
+
+  TextAutosizer* textAutosizer = document().textAutosizer();
+  if (textAutosizer)
+    textAutosizer->newNodeAdded(this);
 }
 
 void LayoutText::dirtyOrDeleteLineBoxesIfNeeded(bool fullLayout) {
   if (fullLayout)
     deleteTextBoxes();
   else if (!m_linesDirty)
     dirtyLineBoxes();
   m_linesDirty = false;
 }
 
@@ skipping 294 matching lines @@
   LayoutRect rect = LayoutRect(
       IntRect(firstRunX(), firstRunY(), linesBox.width(), linesBox.height()));
   LayoutBlock* block = containingBlock();
   if (block && hasTextBoxes())
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink