Bring in the latest json_rpc_2 and barback.

DEPS

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 vars = {
   # The dart_root is the root of our sdk checkout. This is normally
   # simply sdk, but if using special gclient specs it can be different.
   "dart_root": "sdk",
 
   # The svn location to pull out dependencies from
@@ skipping 23 matching lines @@
   "gyp_rev": "@1752",
   "co19_rev": "@f95f109fea67127a220958794ef5200a63cb454c",
   "chromium_url": "http://src.chromium.org/svn",
   "chromium_git": "https://chromium.googlesource.com",
 
   # Revisions of /third_party/* dependencies.
   "7zip_rev" : "@19997",
   "analyzer_cli_rev" : "@7436b45b160f99e806bef2aafd1e971e1aedfc4d",
   "args_tag": "@0.13.0",
   "async_tag": "@1.2.0",
-  "barback_tag" : "@0.15.2+5",
+  "barback_tag" : "@0.15.2+6",
   "charcode_tag": "@1.1.0",
   "chrome_rev" : "@19997",
   "clang_rev" : "@28450",
   "cli_util_tag" : "@0.0.1+2",
   "collection_rev": "@1da9a07f32efa2ba0c391b289e2037391e31da0e",
   "crypto_rev" : "@2df57a1e26dd88e8d0614207d4b062c73209917d",
   "csslib_tag" : "@0.12.0",
   "dartdoc_tag" : "@v0.1.0+5",
   "dart_services_rev" : "@7aea2574e6f3924bf409a80afb8ad52aa2be4f97",
   "dart_style_tag": "@0.1.8+2",
   "dev_compiler_rev": "@0.1.3",
   "fake_async_rev" : "@38614",
   "firefox_jsshell_rev" : "@45554",
   "glob_rev": "@704cf75e4f26b417505c5c611bdaacd8808467dd",
   "gsutil_rev" : "@33376",
   "html_tag" : "@0.12.1+1",
   "http_rev" : "@9b93e1542c753090c50b46ef1592d44bc858bfe7",
   "http_multi_server_tag" : "@1.3.2",
   "http_parser_rev" : "@8b179e36aba985208e4c5fb15cfddd386b6370a4",
   "http_throttle_rev" : "@a81f08be942cdd608883c7b67795c12226abc235",
   "idl_parser_rev": "@6316d5982dc24b34d09dd8b10fbeaaff28d83a48",
   "intl_rev": "@32047558bd220a53c1f4d93a26d54b83533b1475",
   "jinja2_rev": "@2222b31554f03e62600cd7e383376a7c187967a1",
-  "json_rpc_2_rev": "@a38eefd116d910199de205f962af92fed87c164c",
+  "json_rpc_2_tag": "@1.1.1",
   "linter_tag": "@0.1.0",
   "logging_rev": "@85d83e002670545e9039ad3985f0018ab640e597",
   "markdown_rev": "@56b0fd6c018d6103862d07e8e27407b9ea3b963d",
   "matcher_tag": "@0.12.0",
   "metatest_rev": "@e5aa8e4e19fc4188ac2f6d38368a47d8f07c3df1",
   "mime_rev": "@75890811d4af5af080351ba8a2853ad4c8df98dd",
   "mustache4dart_rev" : "@5724cfd85151e5b6b53ddcd3380daf188fe47f92",
   "net_nss_rev": "@f81948e9a402db94287a43bb34a07ee0daf56cb5",
   "nss_rev": "@87b96db4268293187d7cf741907a6d5d1d8080e0",
   "oauth2_rev": "@1bff41f4d54505c36f2d1a001b83b8b745c452f5",
@@ skipping 130 matching lines @@
       (Var("github_mirror") % "http_multi_server") +
       Var("http_multi_server_tag"),
   Var("dart_root") + "/third_party/pkg/http_parser":
       (Var("github_mirror") % "http_parser") + Var("http_parser_rev"),
   Var("dart_root") + "/third_party/pkg/http_throttle":
       (Var("github_mirror") % "http_throttle") +
       Var("http_throttle_rev"),
   Var("dart_root") + "/third_party/pkg/intl":
       (Var("github_mirror") % "intl") + Var("intl_rev"),
   Var("dart_root") + "/third_party/pkg/json_rpc_2":
-      (Var("github_mirror") % "json_rpc_2") + Var("json_rpc_2_rev"),
+      (Var("github_mirror") % "json_rpc_2") + Var("json_rpc_2_tag"),
   Var("dart_root") + "/third_party/pkg/linter":
       (Var("github_mirror") % "linter") + Var("linter_tag"),
   Var("dart_root") + "/third_party/pkg/logging":
       (Var("github_mirror") % "logging") + Var("logging_rev"),
   Var("dart_root") + "/third_party/pkg/markdown":
       "https://chromium.googlesource.com/external/github.com" +
       "/dpeek/dart-markdown.git" + Var("markdown_rev"),
   Var("dart_root") + "/third_party/pkg/matcher":
       (Var("github_mirror") % "matcher") + Var("matcher_tag"),
   Var("dart_root") + "/third_party/pkg/metatest":
@@ skipping 144 matching lines @@
       '--no_resume',
       '--bucket',
       'dart-dependencies',
       '-d',
       '-r',
       Var('dart_root') + '/third_party/d8',
     ],
   },
 
 ]