Cache contains only ascii in StringImpl

third_party/WebKit/Source/wtf/text/WTFString.h

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple 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 387 matching lines @@
   static String fromUTF8(const CString&);
 
   // Tries to convert the passed in string to UTF-8, but will fall back to
   // Latin-1 if the string is not valid UTF-8.
   static String fromUTF8WithLatin1Fallback(const LChar*, size_t);
   static String fromUTF8WithLatin1Fallback(const char* s, size_t length) {
     return fromUTF8WithLatin1Fallback(reinterpret_cast<const LChar*>(s),
                                       length);
   }
 
-  bool containsOnlyASCII() const;
+  bool containsOnlyASCII() const {
+    return !m_impl || m_impl->containsOnlyASCII();
+  }
   bool containsOnlyLatin1() const;
   bool containsOnlyWhitespace() const {
     return !m_impl || m_impl->containsOnlyWhitespace();
   }
 
   size_t charactersSizeInBytes() const {
     return m_impl ? m_impl->charactersSizeInBytes() : 0;
   }
 
   // Hash table deleted values, which are only constructed and never copied or
@@ skipping 127 matching lines @@
 
 #ifdef __OBJC__
 // This is for situations in WebKit where the long standing behavior has been
 // "nil if empty", so we try to maintain longstanding behavior for the sake of
 // entrenched clients
 inline NSString* nsStringNilIfEmpty(const String& str) {
   return str.isEmpty() ? nil : (NSString*)str;
 }
 #endif
 
-inline bool String::containsOnlyASCII() const {
-  if (isEmpty())
-    return true;
-
-  if (is8Bit())
-    return charactersAreAllASCII(characters8(), m_impl->length());
-
-  return charactersAreAllASCII(characters16(), m_impl->length());
-}
-
 WTF_EXPORT int codePointCompare(const String&, const String&);
 
 inline bool codePointCompareLessThan(const String& a, const String& b) {
   return codePointCompare(a.impl(), b.impl()) < 0;
 }
 
 WTF_EXPORT int codePointCompareIgnoringASCIICase(const String&, const char*);
 
 template <bool isSpecialCharacter(UChar)>
 inline bool String::isAllSpecialCharacters() const {
@@ skipping 54 matching lines @@
 using WTF::String;
 using WTF::emptyString;
 using WTF::emptyString16Bit;
 using WTF::charactersAreAllASCII;
 using WTF::equal;
 using WTF::find;
 using WTF::isSpaceOrNewline;
 
 #include "wtf/text/AtomicString.h"
 #endif  // WTFString_h