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

chrome/common/extensions/extension_l10n_util_unittest.cc

Index: chrome/common/extensions/extension_l10n_util_unittest.cc
diff --git a/chrome/common/extensions/extension_l10n_util_unittest.cc b/chrome/common/extensions/extension_l10n_util_unittest.cc
index 99b67de58281e9fc89d684d31671d34e872ab405..182875e8dc8dd2303aac584aec9ab2b8158f6c25 100644
--- a/chrome/common/extensions/extension_l10n_util_unittest.cc
+++ b/chrome/common/extensions/extension_l10n_util_unittest.cc
@@ -210,11 +210,11 @@ TEST(ExtensionL10nUtil, LoadMessageCatalogsBadJSONFormat) {
   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) {