Add support for "additional_mirrors" property in trybot configs.

scripts/slave/recipes/chromium.expected/full_chromium_gpu_GPU_Linux_Builder.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
-      "chromium.gpu.fyi",
+      "chromium.gpu",
       "--builder",
-      "GPU NextGen Linux Builder",
+      "GPU Linux Builder",
       "--slave",
       "TestSlavename",
       "--spec",
       "cache_dir = None\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'}, {'custom_deps': {'src/chrome/test/data/firefox2_profile/searchplugins': None, 'src/chrome/test/data/firefox2_searchplugins': None, 'src/chrome/test/data/firefox3_profile/searchplugins': None, 'src/chrome/test/data/firefox3_searchplugins': None, 'src/chrome/test/data/osdd': None, 'src/chrome/test/data/perf/frame_rate/private': None, 'src/chrome/test/data/plugin': None, 'src/chrome/test/data/ssl/certs': None, 'src/data/autodiscovery': None, 'src/data/esctf': None, 'src/data/mach_ports': None, 'src/data/memory_test': None, 'src/data/mozilla_js_tests': None, 'src/data/page_cycler': None, 'src/data/selenium_core': None, 'src/data/tab_switching': None, 'src/tools/grit/grit/test/data': None, 'src/webkit/data/bmp_decoder': None, 'src/webkit/data/ico_decoder': None, 'src/webkit/data/test_shell/plugins': None, 'src/webkit/data/xbm_decoder': None}, 'deps_file': 'DEPS', 'managed': True, 'name': 'src-internal', 'url': 'svn://svn-mirror.golo.chromium.org/chrome-internal/trunk/src-internal'}]",
       "--root",
       "src",
       "--revision_mapping_file",
       "{\"src\": \"got_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\"}",
       "--output_json",
       "/path/to/tmp/json",
@@ skipping 93 matching lines @@
       "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "archive_gpu_tests=1 component=static_library ffmpeg_branding=Chrome gomadir='[BUILD]/goma' internal_gles2_conform_tests=1 proprietary_codecs=1 target_arch=x64 test_isolation_mode=prepare use_goma=1"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
-      "[SLAVE_BUILD]/src/testing/buildbot/chromium.gpu.fyi.json",
+      "[SLAVE_BUILD]/src/testing/buildbot/chromium.gpu.json",
       "/path/to/tmp/json"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "read test spec",
     "~followup_annotations": [
-      "@@@STEP_TEXT@path: [SLAVE_BUILD]/src/testing/buildbot/chromium.gpu.fyi.json@@@",
+      "@@@STEP_TEXT@path: [SLAVE_BUILD]/src/testing/buildbot/chromium.gpu.json@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
-      "@@@STEP_LOG_LINE@json.output@  \"Linux NextGen Release (NVIDIA)\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"Linux Release (NVIDIA)\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"gtest_tests\": [@@@",
       "@@@STEP_LOG_LINE@json.output@      {@@@",
       "@@@STEP_LOG_LINE@json.output@        \"swarming\": {@@@",
       "@@@STEP_LOG_LINE@json.output@          \"can_use_on_swarming_builders\": true@@@",
       "@@@STEP_LOG_LINE@json.output@        }, @@@",
       "@@@STEP_LOG_LINE@json.output@        \"test\": \"browser_tests\"@@@",
       "@@@STEP_LOG_LINE@json.output@      }@@@",
       "@@@STEP_LOG_LINE@json.output@    ]@@@",
       "@@@STEP_LOG_LINE@json.output@  }@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/testing/scripts/get_compile_targets.py",
       "--output",
       "/path/to/tmp/json",
       "--",
       "--build-config-fs",
       "Release",
       "--use-src-side-runtest-py",
       "--paths",
       "{\"build\": \"[BUILD]\", \"checkout\": \"[SLAVE_BUILD]/src\"}",
       "--properties",
-      "{\"buildername\": \"GPU NextGen Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.gpu.fyi\", \"slavename\": \"TestSlavename\", \"target_platform\": \"linux\"}"
+      "{\"buildername\": \"GPU Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.gpu\", \"slavename\": \"TestSlavename\", \"target_platform\": \"linux\"}"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "get compile targets for scripts",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
@@ skipping 16 matching lines @@
     "cwd": "[SLAVE_BUILD]",
     "name": "clean isolated files"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/tools/mb/mb.py",
       "gen",
       "-m",
-      "chromium.gpu.fyi",
+      "chromium.gpu",
       "-b",
-      "GPU NextGen Linux Builder",
+      "GPU Linux Builder",
       "--config-file",
       "[SLAVE_BUILD]/src/tools/mb/mb_config.pyl",
       "--goma-dir",
       "[BUILD]/goma",
       "--swarming-targets-file",
       "browser_tests\n",
       "//out/Release"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "generate_build_files"
@@ skipping 65 matching lines @@
   },
   {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/zip_build.py",
       "--target",
       "Release",
       "--build-url",
-      "gs://chromium-gpu-fyi-archive/chromium.gpu.fyi/GPU NextGen Linux Builder",
+      "gs://chromium-gpu-fyi-archive/chromium.gpu/GPU Linux Builder",
       "--build_revision",
       "f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
       "--factory-properties",
-      "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"GPU NextGen Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.gpu.fyi\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
+      "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"GPU Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.gpu\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
-      "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"GPU NextGen Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.gpu.fyi\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
+      "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"GPU Linux Builder\", \"buildnumber\": 571, \"mastername\": \"chromium.gpu\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "package build"
   },
   {
     "cmd": [],
     "cwd": "[SLAVE_BUILD]",
     "name": "trigger",
     "trigger_specs": [
       {
-        "builder_name": "Linux NextGen Release (NVIDIA)",
+        "builder_name": "Linux Release (NVIDIA)",
         "properties": {
           "parent_got_angle_revision": "fac9503c46405f77757b9a728eb85b8d7bc6080c",
           "parent_got_angle_revision_cp": "refs/heads/master@{#297276}",
           "parent_got_nacl_revision": "d998e125e8253980d76e269b7982aeeefc1b9b50",
           "parent_got_nacl_revision_cp": "refs/heads/master@{#274981}",
           "parent_got_revision": "f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
           "parent_got_revision_cp": "refs/heads/master@{#170242}",
           "parent_got_swarming_client_revision": "a0ee5d99f1d4b38ddaa4c759c837980b63b99566",
           "parent_got_swarming_client_revision_cp": "refs/heads/master@{#276089}",
           "parent_got_v8_revision": "801ada225ddc271c132c3a35f03975671d43e399",
           "parent_got_v8_revision_cp": "refs/heads/master@{#43426}",
           "parent_got_webrtc_revision": "0f90628433546e61d9268596da93418c623137f4",
           "parent_got_webrtc_revision_cp": "refs/heads/master@{#120644}"
         }
       }
     ],
     "~followup_annotations": [
-      "@@@STEP_TEXT@Linux NextGen Release (NVIDIA)@@@"
+      "@@@STEP_TEXT@Linux Release (NVIDIA)@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]