Add test case for WebRTC patch on Chromium trybots.

scripts/slave/recipes/chromium_trybot.expected/use_webrtc_patch_on_chromium_trybot.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]\\resources\\bot_update.py",
       "--master",
       "tryserver.chromium.win",
       "--builder",
       "win_chromium_rel_ng",
       "--slave",
       "TestSlavename",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'custom_vars': {'googlecode_url': 'svn://svn-mirror.golo.chromium.org/%s', 'nacl_trunk': 'svn://svn-mirror.golo.chromium.org/native_client/trunk', 'sourceforge_url': 'svn://svn-mirror.golo.chromium.org/%(repo)s', 'webkit_trunk': 'svn://svn-mirror.golo.chromium.org/blink/trunk'}, 'deps_file': 'DEPS', 'managed': True, 'name': 'src', 'url': 'svn://svn-mirror.golo.chromium.org/chrome/trunk/src'}]",
       "--root",
-      "src",
+      "src\\third_party",
       "--revision_mapping_file",
       "{\"src\": \"got_revision\", \"src/buildtools\": \"got_buildtools_revision\", \"src/native_client\": \"got_nacl_revision\", \"src/third_party/angle\": \"got_angle_revision\", \"src/third_party/webrtc\": \"got_webrtc_revision\", \"src/tools/swarming_client\": \"got_swarming_client_revision\", \"src/v8\": \"got_v8_revision\"}",
       "--git-cache-dir",
       "[GIT_CACHE]",
       "--issue",
       "12853011",
       "--patchset",
       "1",
       "--rietveld_server",
       "https://codereview.chromium.org",
@@ skipping 38 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    \"src/tools/swarming_client\": {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"repository\": \"https://fake.org/src/tools/swarming_client.git\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"revision\": \"a0ee5d99f1d4b38ddaa4c759c837980b63b99566\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }, @@@",
       "@@@STEP_LOG_LINE@json.output@    \"src/v8\": {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"repository\": \"https://fake.org/src/v8.git\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"revision\": \"801ada225ddc271c132c3a35f03975671d43e399\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"patch_failure\": false, @@@",
-      "@@@STEP_LOG_LINE@json.output@  \"patch_root\": \"src\", @@@",
+      "@@@STEP_LOG_LINE@json.output@  \"patch_root\": \"src\\\\third_party\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"properties\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_angle_revision\": \"fac9503c46405f77757b9a728eb85b8d7bc6080c\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_angle_revision_cp\": \"refs/heads/master@{#297276}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_buildtools_revision\": \"f0319a328b2809876916353cb994259692140934\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_buildtools_revision_cp\": \"refs/heads/master@{#182578}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_nacl_revision\": \"d998e125e8253980d76e269b7982aeeefc1b9b50\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_nacl_revision_cp\": \"refs/heads/master@{#274981}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_revision\": \"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_revision_cp\": \"refs/heads/master@{#170242}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_swarming_client_revision\": \"a0ee5d99f1d4b38ddaa4c759c837980b63b99566\", @@@",
@@ skipping 165 matching lines @@
     "cwd": "RECIPE_PACKAGE_REPO[depot_tools]",
     "name": "ensure git tooling on windows"
   },
   {
     "cmd": [
       "RECIPE_PACKAGE_REPO[depot_tools]\\git.bat",
       "diff",
       "--cached",
       "--name-only"
     ],
-    "cwd": "[SLAVE_BUILD]\\src",
+    "cwd": "[SLAVE_BUILD]\\src\\third_party",
     "name": "git diff to analyze patch",
     "stdout": "/path/to/tmp/",
     "~followup_annotations": [
-      "@@@STEP_LOG_LINE@files@README.md@@@",
-      "@@@STEP_LOG_LINE@files@foo/bar/baz.py@@@",
+      "@@@STEP_LOG_LINE@files@third_party/foo.cc@@@",
       "@@@STEP_LOG_END@files@@@",
       "@@@SET_BUILD_PROPERTY@subproject_tag@\"chromium\"@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]\\src\\testing\\buildbot\\trybot_analyze_config.json",
@@ skipping 21 matching lines @@
       "python",
       "-u",
       "[SLAVE_BUILD]\\src\\tools\\mb\\mb.py",
       "analyze",
       "-m",
       "tryserver.chromium.win",
       "-b",
       "win_chromium_rel_ng",
       "-v",
       "//out/Release",
-      "{\"additional_compile_targets\": [\"chromium_builder_tests\"], \"files\": [\"README.md\", \"foo/bar/baz.py\"], \"test_targets\": [\"mini_installer\"]}",
+      "{\"additional_compile_targets\": [\"chromium_builder_tests\"], \"files\": [\"third_party/foo.cc\"], \"test_targets\": [\"mini_installer\"]}",
       "/path/to/tmp/json"
     ],
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json"
     },
     "name": "analyze",
     "~followup_annotations": [
       "@@@STEP_TEXT@No compile necessary@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"compile_targets\": [], @@@",
-      "@@@STEP_LOG_LINE@json.output@  \"status\": \"No dependencies\", @@@",
+      "@@@STEP_LOG_LINE@json.output@  \"status\": \"No dependency\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"test_targets\": []@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@",
       "@@@STEP_LOG_LINE@analyze_details@{@@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"additional_compile_targets\": [@@@",
       "@@@STEP_LOG_LINE@analyze_details@    \"chromium_builder_tests\"@@@",
       "@@@STEP_LOG_LINE@analyze_details@  ], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"compile_targets\": [], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"self.m.filter.compile_targets\": [], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"self.m.filter.test_targets\": [], @@@",
@@ skipping 11 matching lines @@
       "import sys; sys.exit(0)"
     ],
     "name": "mark: before_tests"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]