Update JSONReader to take base::StringPiece instead of std::string

base/json/json_parser.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/json/json_parser.h"
 
 #include "base/float_util.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/string_number_conversions.h"
+#include "base/string_piece.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/third_party/icu/icu_utf.h"
 #include "base/utf_string_conversion_utils.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 
 namespace base {
 namespace internal {
 
@@ skipping 176 matching lines @@
       line_number_(0),
       index_last_line_(0),
       error_code_(JSONReader::JSON_NO_ERROR),
       error_line_(0),
       error_column_(0) {
 }
 
 JSONParser::~JSONParser() {
 }
 
-Value* JSONParser::Parse(const std::string& input) {
+Value* JSONParser::Parse(const StringPiece& input) {
   // TODO(rsesek): Windows has problems with StringPiece/hidden roots. Fix
   // <http://crbug.com/126107> when my Windows box arrives.
 #if defined(OS_WIN)
   options_ |= JSON_DETACHABLE_CHILDREN;
 #endif
 
   std::string input_copy;
   // If the children of a JSON root can be detached, then hidden roots cannot
   // be used, so do not bother copying the input because StringPiece will not
   // be used anywhere.
   if (!(options_ & JSON_DETACHABLE_CHILDREN)) {
-    input_copy = input;
+    input_copy = input.as_string();
     start_pos_ = input_copy.data();
   } else {
     start_pos_ = input.data();
   }
   pos_ = start_pos_;
   end_pos_ = start_pos_ + input.length();
   index_ = 0;
   line_number_ = 1;
   index_last_line_ = 0;
 
@@ skipping 730 matching lines @@
                                            const std::string& description) {
   if (line || column) {
     return StringPrintf("Line: %i, column: %i, %s",
         line, column, description.c_str());
   }
   return description;
 }
 
 }  // namespace internal
 }  // namespace base