Fix shadowing warning in json_parser on VS2015

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/strings/string_number_conversions.h"
@@ skipping 410 matching lines @@
 }
 
 bool JSONParser::EatComment() {
   if (*pos_ != '/' || !CanConsume(1))
     return false;
 
   char next_char = *NextChar();
   if (next_char == '/') {
     // Single line comment, read to newline.
     while (CanConsume(1)) {
-      char next_char = *NextChar();
+      next_char = *NextChar();
       if (next_char == '\n' || next_char == '\r')
         return true;
     }
   } else if (next_char == '*') {
     char previous_char = '\0';
     // Block comment, read until end marker.
     while (CanConsume(1)) {
       next_char = *NextChar();
       if (previous_char == '*' && next_char == '/') {
         // EatWhitespaceAndComments will inspect pos_, which will still be on
@@ skipping 514 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