Upgrade dartdoc to v0.12.0.

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",
 
   # We use mirrors of all github repos to guarantee reproducibility and
@@ skipping 44 matching lines @@
   "chrome_rev" : "@19997",
   "cli_util_tag" : "@0.1.0",
   "code_transformers_tag": "@v0.5.1",
   "collection_tag": "@1.13.0",
   "convert_tag": "@2.0.1",
   "crypto_tag" : "@2.0.1",
   "csslib_tag" : "@0.13.3+1",
   "dart2js_info_tag" : "@0.5.4+2",
   "dart_services_rev" : "@7aea2574e6f3924bf409a80afb8ad52aa2be4f97",
   "dart_style_tag": "@1.0.6",
-  "dartdoc_tag" : "@v0.9.14-dev",
+  "dartdoc_tag" : "@v0.12.0",
   "fixnum_tag": "@0.10.5",
   "func_tag": "@1.0.0",
   "glob_tag": "@1.1.3",
   "html_tag" : "@0.13.1",
   "http_multi_server_tag" : "@2.0.3",
   "http_parser_tag" : "@3.1.1",
   "http_tag" : "@0.11.3+9",
   "http_throttle_tag" : "@1.0.1",
   "idl_parser_rev": "@7fbe68cab90c38147dee4f48c30ad0d496c17915",
   "initialize_tag": "@v0.6.2+5",
   "intl_tag": "@0.14.0",
   "isolate_tag": "@1.0.0",
   "jinja2_rev": "@2222b31554f03e62600cd7e383376a7c187967a1",
   "json_rpc_2_tag": "@2.0.4",
   "linter_tag": "@0.1.31",
   "logging_tag": "@0.11.3+1",
   "markdown_tag": "@0.11.2",
   "matcher_tag": "@0.12.0+2",
   "metatest_tag": "@0.2.2+3",
   "mime_rev": "@75890811d4af5af080351ba8a2853ad4c8df98dd",
-  "mustache4dart_tag" : "@v1.0.10",
+  "mustache4dart_tag" : "@v1.1.0",
   "oauth2_tag": "@1.0.2",
   "observable_tag": "@0.17.0",
   "observatory_pub_packages_rev": "@26aad88f1c1915d39bbcbff3cad589e2402fdcf1",
   "observe_tag": "@0.15.0",
   "package_config_tag": "@1.0.0",
   "package_resolver_tag": "@1.0.2+1",
   "path_tag": "@1.4.1",
   "plugin_tag": "@0.2.0",
   "ply_rev": "@604b32590ffad5cbb82e4afef1d305512d06ae93",
   "pool_tag": "@1.3.0",
@@ skipping 12 matching lines @@
   "source_map_stack_trace_tag": "@1.1.4",
   "source_maps-0.9.4_rev": "@38524",
   "source_maps_tag": "@0.10.4",
   "source_span_tag": "@1.4.0",
   "stack_trace_tag": "@1.7.2",
   "stream_channel_tag": "@1.6.1",
   "string_scanner_tag": "@1.0.1",
   "sunflower_rev": "@879b704933413414679396b129f5dfa96f7a0b1e",
   "test_reflective_loader_tag": "@0.1.0",
   "test_tag": "@0.12.18+1",
+  "tuple_tag": "@v1.0.1",
   "typed_data_tag": "@1.1.3",
   "usage_tag": "@v3.0.0+1",
   "utf_tag": "@0.9.0+3",
   "watcher_tag": "@0.9.7+3",
   "web_components_rev": "@6349e09f9118dce7ae1b309af5763745e25a9d61",
   "web_socket_channel_tag": "@1.0.4",
   "WebCore_rev": "@3c45690813c112373757bbef53de1602a62af609",
   "yaml_tag": "@2.1.12",
   "zlib_rev": "@c3d0a6190f2f8c924a05ab6cc97b8f975bddd33f",
 }
@@ skipping 188 matching lines @@
       (Var("github_mirror") % "string_scanner") +
       Var("string_scanner_tag"),
   Var("dart_root") + "/third_party/sunflower":
       (Var("github_mirror") % "sample-sunflower") +
       Var("sunflower_rev"),
   Var("dart_root") + "/third_party/pkg/test":
       (Var("github_mirror") % "test") + Var("test_tag"),
   Var("dart_root") + "/third_party/pkg/test_reflective_loader":
       (Var("github_mirror") % "test_reflective_loader") +
       Var("test_reflective_loader_tag"),
+  Var("dart_root") + "/third_party/pkg/tuple":
+      (Var("github_dartlang") % "tuple") + Var("tuple_tag"),
   Var("dart_root") + "/third_party/pkg/typed_data":
       (Var("github_mirror") % "typed_data") + Var("typed_data_tag"),
   Var("dart_root") + "/third_party/pkg/usage":
       (Var("github_mirror") % "usage") + Var("usage_tag"),
   Var("dart_root") + "/third_party/pkg/utf":
       (Var("github_mirror") % "utf") + Var("utf_tag"),
   Var("dart_root") + "/third_party/pkg/watcher":
       (Var("github_mirror") % "watcher") + Var("watcher_tag"),
   Var("dart_root") + "/third_party/pkg/web_components":
       (Var("github_mirror") % "web-components") +
@@ skipping 149 matching lines @@
     # Update the Windows toolchain if necessary.
     'name': 'win_toolchain',
     'pattern': '.',
     'action': ['python', 'sdk/build/vs_toolchain.py', 'update'],
   },
   {
     "pattern": ".",
     "action": ["python", Var("dart_root") + "/tools/generate_buildfiles.py"],
   },
 ]