Add Experimental Feature to Force the Complex Text Path

Source/platform/fonts/Font.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (c) 2007, 2008, 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
@@ skipping 280 matching lines @@
     FontCachePurgePreventer purgePreventer;
 
     if (codePath(TextRunPaintInfo(run)) != ComplexPath && !fontDescription().typesettingFeatures())
         return offsetForPositionForSimpleText(run, x, includePartialGlyphs);
 
     return offsetForPositionForComplexText(run, x, includePartialGlyphs);
 }
 
 CodePath Font::codePath(const TextRunPaintInfo& runInfo) const
 {
+    if (RuntimeEnabledFeatures::alwaysUseComplexTextEnabled())
+        return ComplexPath;
+
     const TextRun& run = runInfo.run;
 
     if (fontDescription().typesettingFeatures() && (runInfo.from || runInfo.to != run.length()))
         return ComplexPath;
 
     if (m_fontDescription.featureSettings() && m_fontDescription.featureSettings()->size() > 0 && m_fontDescription.letterSpacing() == 0)
         return ComplexPath;
 
     if (m_fontDescription.isVerticalBaseline())
         return ComplexPath;
@@ skipping 526 matching lines @@
 {
     return m_fontFallbackList && m_fontFallbackList->loadingCustomFonts();
 }
 
 bool Font::isFallbackValid() const
 {
     return !m_fontFallbackList || m_fontFallbackList->isValid();
 }
 
 } // namespace blink