Add struct traits for base::Value.

base/values.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/values.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 100 matching lines @@
 }
 
 bool Value::GetAsString(string16* out_value) const {
   return false;
 }
 
 bool Value::GetAsString(const StringValue** out_value) const {
   return false;
 }
 
+bool Value::GetAsString(StringPiece* out_value) const {
+  return false;
+}
+
 bool Value::GetAsList(ListValue** out_value) {
   return false;
 }
 
 bool Value::GetAsList(const ListValue** out_value) const {
   return false;
 }
 
 bool Value::GetAsDictionary(DictionaryValue** out_value) {
   return false;
@@ skipping 149 matching lines @@
     *out_value = UTF8ToUTF16(value_);
   return true;
 }
 
 bool StringValue::GetAsString(const StringValue** out_value) const {
   if (out_value)
     *out_value = this;
   return true;
 }
 
+bool StringValue::GetAsString(StringPiece* out_value) const {
+  if (out_value)
+    *out_value = value_;
+  return true;
+}
+
 StringValue* StringValue::DeepCopy() const {
   return new StringValue(value_);
 }
 
 bool StringValue::Equals(const Value* other) const {
   if (other->GetType() != GetType())
     return false;
   std::string lhs, rhs;
   return GetAsString(&lhs) && other->GetAsString(&rhs) && lhs == rhs;
 }
@@ skipping 865 matching lines @@
 }
 
 std::ostream& operator<<(std::ostream& out, const Value::Type& type) {
   if (static_cast<int>(type) < 0 ||
       static_cast<size_t>(type) >= arraysize(kTypeNames))
     return out << "Invalid Type (index = " << static_cast<int>(type) << ")";
   return out << Value::GetTypeName(type);
 }
 
 }  // namespace base