Fix the inconsistent problem while the content of textNodes is changed

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

Index: third_party/WebKit/Source/core/layout/LayoutText.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutText.cpp b/third_party/WebKit/Source/core/layout/LayoutText.cpp
index a9c752da008b776c0b185fa9edad9f12291e07f9..a8e43ab43b0774ba9b7a11cb1fa9eae68923289d 100644
--- a/third_party/WebKit/Source/core/layout/LayoutText.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutText.cpp
@@ -34,6 +34,7 @@
 #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"
@@ -209,6 +210,10 @@ void LayoutText::styleDidChange(StyleDifference diff,
   // 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() {
@@ -1666,6 +1671,10 @@ void LayoutText::setText(PassRefPtr<StringImpl> text, bool force) {
 
   if (AXObjectCache* cache = document().existingAXObjectCache())
     cache->textChanged(this);
+
+  TextAutosizer* textAutosizer = document().textAutosizer();
+  if (textAutosizer)
+    textAutosizer->newNodeAdded(this);
 }
 
 void LayoutText::dirtyOrDeleteLineBoxesIfNeeded(bool fullLayout) {