Add a check that the Chromedriver prebuilt name is expected.

scripts/slave/recipe_modules/chromedriver/example.expected/Android_ChromeDriver_unexpected_prebuilt.json

 [
   {
     "cmd": [
       "python",
       "-u",
-      "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
-      "[BUILDER_CACHE]/linux",
-      "511"
-    ],
-    "name": "makedirs checkout path",
-    "~followup_annotations": [
-      "@@@STEP_LOG_LINE@python.inline@@@@",
-      "@@@STEP_LOG_LINE@python.inline@import sys, os@@@",
-      "@@@STEP_LOG_LINE@python.inline@path = sys.argv[1]@@@",
-      "@@@STEP_LOG_LINE@python.inline@mode = int(sys.argv[2])@@@",
-      "@@@STEP_LOG_LINE@python.inline@if not os.path.isdir(path):@@@",
-      "@@@STEP_LOG_LINE@python.inline@  if os.path.exists(path):@@@",
-      "@@@STEP_LOG_LINE@python.inline@    print \"%s exists but is not a dir\" % path@@@",
-      "@@@STEP_LOG_LINE@python.inline@    sys.exit(1)@@@",
-      "@@@STEP_LOG_LINE@python.inline@  os.makedirs(path, mode)@@@",
-      "@@@STEP_LOG_END@python.inline@@@"
-    ]
-  },
-  {
-    "cmd": [
-      "python",
-      "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
-      "tryserver.chromium.linux",
+      "chromium.testing.master",
       "--builder",
-      "linux_chromium_rel_ng",
+      "Android ChromeDriver Tests Example",
       "--slave",
-      "TestSlavename",
+      "slavename",
       "--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",
       "--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",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD",
+      "--force",
       "--output_manifest"
     ],
-    "cwd": "[BUILDER_CACHE]/linux",
     "env": {
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "bot_update",
     "~followup_annotations": [
-      "step returned non-zero exit code: 1",
       "@@@STEP_TEXT@Some step text@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"did_run\": true, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"fixed_revisions\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"src\": \"HEAD\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"manifest\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"src\": {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"repository\": \"https://fake.org/src.git\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"revision\": \"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\"@@@",
@@ skipping 38 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    \"got_swarming_client_revision_cp\": \"refs/heads/master@{#276089}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_v8_revision\": \"801ada225ddc271c132c3a35f03975671d43e399\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_v8_revision_cp\": \"refs/heads/master@{#43426}\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_webrtc_revision\": \"0f90628433546e61d9268596da93418c623137f4\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_webrtc_revision_cp\": \"refs/heads/master@{#120644}\"@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"root\": \"src\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"step_text\": \"Some step text\"@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@",
-      "@@@STEP_EXCEPTION@@@",
       "@@@SET_BUILD_PROPERTY@got_nacl_revision@\"d998e125e8253980d76e269b7982aeeefc1b9b50\"@@@",
       "@@@SET_BUILD_PROPERTY@got_swarming_client_revision@\"a0ee5d99f1d4b38ddaa4c759c837980b63b99566\"@@@",
       "@@@SET_BUILD_PROPERTY@got_buildtools_revision_cp@\"refs/heads/master@{#182578}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_webrtc_revision@\"0f90628433546e61d9268596da93418c623137f4\"@@@",
       "@@@SET_BUILD_PROPERTY@got_revision@\"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\"@@@",
       "@@@SET_BUILD_PROPERTY@got_nacl_revision_cp@\"refs/heads/master@{#274981}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_angle_revision@\"fac9503c46405f77757b9a728eb85b8d7bc6080c\"@@@",
       "@@@SET_BUILD_PROPERTY@got_v8_revision@\"801ada225ddc271c132c3a35f03975671d43e399\"@@@",
       "@@@SET_BUILD_PROPERTY@got_v8_revision_cp@\"refs/heads/master@{#43426}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_swarming_client_revision_cp@\"refs/heads/master@{#276089}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_webrtc_revision_cp@\"refs/heads/master@{#120644}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_revision_cp@\"refs/heads/master@{#170242}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_angle_revision_cp@\"refs/heads/master@{#297276}\"@@@",
       "@@@SET_BUILD_PROPERTY@got_buildtools_revision@\"f0319a328b2809876916353cb994259692140934\"@@@"
     ]
   },
   {
+    "cmd": [],
+    "name": "Download Prebuilts"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[BUILD]/scripts/slave/gsutil_download.py",
+      "--url",
+      "gs://chromedriver-data/prebuilts",
+      "--dst",
+      "[TMP_BASE]/prebuilt_tmp_1",
+      "--partial-name",
+      "gs://chromedriver-data/prebuilts/r"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "Download Prebuilts.download latest prebuilt",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
     "cmd": [
       "python",
       "-u",
-      "import sys; sys.exit(0)"
+      "\nimport json, os, sys\nif os.path.exists(sys.argv[1]) and os.path.isdir(sys.argv[1]):\n  with open(sys.argv[2], 'w') as f:\n    json.dump(os.listdir(sys.argv[1]), f)\n",
+      "[TMP_BASE]/prebuilt_tmp_1",
+      "/path/to/tmp/json"
     ],
-    "name": "mark: before_tests",
+    "name": "Download Prebuilts.listdir get prebuilt filename",
     "~followup_annotations": [
-      "@@@SET_BUILD_PROPERTY@failure_hash@\"fed620386b0c58ac55d7fd7707794386f73ef90c\"@@@"
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@json.output@[@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"rNone.zip\"@@@",
+      "@@@STEP_LOG_LINE@json.output@]@@@",
+      "@@@STEP_LOG_END@json.output@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import json, os, sys@@@",
+      "@@@STEP_LOG_LINE@python.inline@if os.path.exists(sys.argv[1]) and os.path.isdir(sys.argv[1]):@@@",
+      "@@@STEP_LOG_LINE@python.inline@  with open(sys.argv[2], 'w') as f:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    json.dump(os.listdir(sys.argv[1]), f)@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_MODULE[recipe_engine::shutil]/resources/rmtree.py",
+      "[TMP_BASE]/prebuilt_tmp_1"
+    ],
+    "name": "Download Prebuilts.rmtree [TMP_BASE]/prebuilt_tmp_1",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
     "name": "$result",
-    "reason": "Infra Failure: Step('bot_update') returned 1",
+    "reason": "Unexpected prebuilt filename: rNone.zip",
     "recipe_result": null,
     "status_code": 1
   }
 ]