Expand WTF::StringView's API to be more like StringPiece.

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2008 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef AtomicString_h
 #define AtomicString_h
 
 #include "wtf/Allocator.h"
 #include "wtf/HashTableDeletedValueType.h"
 #include "wtf/WTFExport.h"
 #include "wtf/text/CString.h"
+#include "wtf/text/StringView.h"
 #include "wtf/text/WTFString.h"
 #include <cstring>
 #include <iosfwd>
 
 namespace WTF {
 
 struct AtomicStringHash;
 
 class WTF_EXPORT AtomicString {
     USING_FAST_MALLOC(AtomicString);
@@ skipping 188 matching lines @@
 
 inline AtomicString AtomicString::fromUTF8(const char* characters)
 {
     if (!characters)
         return nullAtom;
     if (!*characters)
         return emptyAtom;
     return fromUTF8Internal(characters, 0);
 }
 
+inline StringView::StringView(const AtomicString& string)
+    : StringView(string, 0, string.length()) {}
+inline StringView::StringView(const AtomicString& string, unsigned offset, unsigned length)
+    : StringView(string.impl(), offset, length) {}
+inline StringView::StringView(const AtomicString& string, unsigned offset)
+    : StringView(string.impl(), offset) {}
+
 // AtomicStringHash is the default hash for AtomicString
 template<typename T> struct DefaultHash;
 template<> struct DefaultHash<AtomicString> {
     typedef AtomicStringHash Hash;
 };
 
 // Pretty printer for gtest and base/logging.*.  It prepends and appends
 // double-quotes, and escapes chracters other than ASCII printables.
 WTF_EXPORT std::ostream& operator<<(std::ostream&, const AtomicString&);
 
 } // namespace WTF
 
 WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(AtomicString);
 
 using WTF::AtomicString;
 using WTF::nullAtom;
 using WTF::emptyAtom;
 using WTF::starAtom;
 using WTF::xmlAtom;
 using WTF::xmlnsAtom;
 using WTF::xlinkAtom;
 
 #include "wtf/text/StringConcatenate.h"
 #endif // AtomicString_h