Add a check that the Chromedriver prebuilt name is expected.

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "chromium.testing.master",
       "--builder",
       "Android ChromeDriver Tests Example",
@@ skipping 98 matching lines @@
     "name": "Download Prebuilts"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/gsutil_download.py",
       "--url",
       "gs://chromedriver-data/prebuilts",
       "--dst",
-      "[TMP_BASE]/prebuilt_tmp_1/build.zip",
+      "[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",
+      "\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": "Download Prebuilts.listdir get prebuilt filename",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@json.output@[@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"r111111.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[build::zip]/resources/unzip.py"
     ],
     "name": "Download Prebuilts.unzip prebuilt",
-    "stdin": "{\"output\": \"[TMP_BASE]/prebuilt_tmp_1/unzipped\", \"zip_file\": \"[TMP_BASE]/prebuilt_tmp_1/build.zip\"}",
+    "stdin": "{\"output\": \"[TMP_BASE]/prebuilt_tmp_1/unzipped\", \"zip_file\": \"[TMP_BASE]/prebuilt_tmp_1/r111111.zip\"}",
     "~followup_annotations": [
       "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.move(sys.argv[1], sys.argv[2])\n",
       "[TMP_BASE]/prebuilt_tmp_1/unzipped/chromedriver",
@@ skipping 552 matching lines @@
     "~followup_annotations": [
       "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]