chromium_tests: automatically set up test genrators

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 259 matching lines @@
       "--show-path",
       "python",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\cleanup_temp.py"
     ],
     "name": "cleanup_temp"
   },
   {
     "cmd": [
       "python",
       "-u",
+      "RECIPE_MODULE[build::isolate]\\resources\\find_isolated_tests.py",
+      "--build-dir",
+      "[BUILDER_CACHE]\\Win_Builder\\src\\out\\Release_x64",
+      "--clean-isolated-files"
+    ],
+    "name": "clean isolated files"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "[BUILDER_CACHE]\\Win_Builder\\src\\tools\\mb\\mb.py",
       "gen",
       "-m",
       "chromium.perf.fyi",
       "-b",
       "Win Builder",
       "--config-file",
       "[BUILDER_CACHE]\\Win_Builder\\src\\tools\\mb\\mb_config.pyl",
       "--goma-dir",
       "[CACHE]\\cipd\\goma",
+      "--swarming-targets-file",
+      "browser_tests\n",
       "//out/Release_x64"
     ],
     "cwd": "[BUILDER_CACHE]\\Win_Builder\\src",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json"
     },
-    "name": "generate_build_files"
+    "name": "generate_build_files",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@swarming-targets-file.txt@browser_tests@@@",
+      "@@@STEP_LOG_END@swarming-targets-file.txt@@@"
+    ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\tools\\runit.py",
       "--show-path",
       "python",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\compile.py",
       "--gsutil-py-path",
@@ skipping 20 matching lines @@
       "goma",
       "--goma-jsonstatus",
       "/path/to/tmp/json",
       "--goma-service-account-json-file",
       "C:\\creds\\service_accounts\\service-account-goma-client.json",
       "--mode",
       "official",
       "--goma-dir",
       "[CACHE]\\cipd\\goma",
       "--",
+      "browser_tests",
+      "browser_tests_run",
       "chrome",
       "chromium_builder_perf"
     ],
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json"
     },
     "name": "compile",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
       "@@@STEP_LOG_END@json.output (invalid)@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "[BUILDER_CACHE]\\Win_Builder\\src\\tools\\determinism\\remove_build_metadata.py",
+      "--build-dir",
+      "[BUILDER_CACHE]\\Win_Builder\\src\\out\\Release_x64"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "remove_build_metadata"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_MODULE[build::isolate]\\resources\\isolate.py",
+      "[BUILDER_CACHE]\\Win_Builder\\src\\tools\\swarming_client",
+      "batcharchive",
+      "--dump-json",
+      "/path/to/tmp/json",
+      "--isolate-server",
+      "https://isolateserver.appspot.com",
+      "--verbose",
+      "[BUILDER_CACHE]\\Win_Builder\\src\\out\\Release_x64\\browser_tests.isolated.gen.json"
+    ],
+    "name": "isolate tests",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output@{@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"browser_tests\": \"[dummy hash for browser_tests]\"@@@",
+      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_END@json.output@@@"
+    ]
+  },
+  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\tools\\runit.py",
       "--show-path",
       "python",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\zip_build.py",
       "--target",
       "Release_x64",
@@ skipping 89 matching lines @@
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json"
     },
     "name": "process_dumps"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]