Limit optimized LayoutBlockFlowLine width computation to 8bit

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

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc.
  *               All right reserved.
  * Copyright (C) 2010 Google Inc. 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 530 matching lines @@
   float measuredWidth = 0;
   FloatRect glyphBounds;
 
   bool kerningIsEnabled =
       font.getFontDescription().getTypesettingFeatures() & Kerning;
 
 #if OS(MACOSX)
   // FIXME: Having any font feature settings enabled can lead to selection gaps
   // on Chromium-mac. https://bugs.webkit.org/show_bug.cgi?id=113418
   bool canUseCachedWordMeasurements =
-      font.canShapeWordByWord() && !font.getFontDescription().featureSettings();
+      font.canShapeWordByWord() &&
+      !font.getFontDescription().featureSettings() && layoutText.is8Bit();
 #else
-  bool canUseCachedWordMeasurements = font.canShapeWordByWord();
+  bool canUseCachedWordMeasurements =
+      font.canShapeWordByWord() && layoutText.is8Bit();
 #endif
 
   if (canUseCachedWordMeasurements) {
     int lastEndOffset = run->m_start;
     size_t i = findWordMeasurement(layoutText, lastEndOffset, wordMeasurements,
                                    wordMeasurementsIndex);
     for (size_t size = wordMeasurements.size();
          i < size && lastEndOffset < run->m_stop; ++i) {
       const WordMeasurement& wordMeasurement = wordMeasurements[i];
       if (wordMeasurement.startOffset == wordMeasurement.endOffset)
@@ skipping 2021 matching lines @@
 
 bool LayoutBlockFlow::paintedOutputOfObjectHasNoEffectRegardlessOfSize() const {
   // LayoutBlockFlow is in charge of paint invalidation of the first line.
   if (firstLineBox())
     return false;
 
   return LayoutBlock::paintedOutputOfObjectHasNoEffectRegardlessOfSize();
 }
 
 }  // namespace blink