Rewrite base::JSONReader to be 35-40% faster, depending on the input string.

chrome/common/extensions/extension_l10n_util_unittest.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/file_path.h"
 #include "base/file_util.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
@@ skipping 192 matching lines @@
   std::string data = "{ \"name\":";
   ASSERT_TRUE(
       file_util::WriteFile(locale.Append(Extension::kMessagesFilename),
                            data.c_str(), data.length()));
 
   std::set<std::string> valid_locales;
   valid_locales.insert("sr");
   valid_locales.insert("en_US");
   std::string error;
   EXPECT_TRUE(NULL == extension_l10n_util::LoadMessageCatalogs(src_path,
-                                                              "en_US",
-                                                              "sr",
-                                                              valid_locales,
-                                                              &error));
-  EXPECT_EQ("Line: 1, column: 10, Syntax error.", error);
+                                                               "en_US",
+                                                               "sr",
+                                                               valid_locales,
+                                                               &error));
+  EXPECT_EQ("Line: 1, column: 10, Unexpected token.", error);
 }
 
 TEST(ExtensionL10nUtil, LoadMessageCatalogsDuplicateKeys) {
   ScopedTempDir temp;
   ASSERT_TRUE(temp.CreateUniqueTempDir());
 
   FilePath src_path = temp.path().Append(Extension::kLocaleFolder);
   ASSERT_TRUE(file_util::CreateDirectory(src_path));
 
   FilePath locale_1 = src_path.AppendASCII("en");
@@ skipping 381 matching lines @@
   DictionaryValue manifest;
   manifest.SetString(keys::kDefaultLocale, "en_US");
   manifest.SetString(keys::kCurrentLocale, "sr");
 
   ExtensionInfo info(&manifest, "", FilePath(), Extension::LOAD);
 
   EXPECT_TRUE(extension_l10n_util::ShouldRelocalizeManifest(info));
 }
 
 }  // namespace