Optimize for horizontal writing mode

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 1dc82d0421ca71ffdd68fc136f47d99e86112afe..fc8fdd59e19b8e2a3ec43ae0f13d392222718245 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -782,6 +782,9 @@ public:
     void setDirectionSetOnDocumentElement(bool b) { m_directionSetOnDocumentElement = b; }
     void setWritingModeSetOnDocumentElement(bool b) { m_writingModeSetOnDocumentElement = b; }
 
+    bool containsAnyVerticalWritingModes() const { return m_containsAnyVerticalWritingModes; }
+    void setContainsAnyVerticalWritingModes(bool b) { m_containsAnyVerticalWritingModes = b; }
+
     bool execCommand(const String& command, bool userInterface = false, const String& value = String());
     bool queryCommandEnabled(const String& command);
     bool queryCommandIndeterm(const String& command);
@@ -1331,6 +1334,7 @@ private:
 
     bool m_directionSetOnDocumentElement;
     bool m_writingModeSetOnDocumentElement;
+    bool m_containsAnyVerticalWritingModes;
     DocumentTiming m_documentTiming;
     RefPtrWillBeMember<MediaQueryMatcher> m_mediaQueryMatcher;
     bool m_writeRecursionIsTooDeep;