Recipes: make cwd default to slave_build

scripts/slave/recipes/blink_downstream.expected/webkit_tests_unexpected_error.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "client.v8",
       "--builder",
       "V8-Blink Linux 64",
       "--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}, '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_cr_revision\", \"src/native_client\": \"got_nacl_revision\", \"src/third_party/WebKit\": \"got_webkit_revision\", \"src/third_party/webrtc\": \"got_webrtc_revision\", \"src/tools/swarming_client\": \"got_swarming_client_revision\", \"src/v8\": \"got_revision\"}",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@HEAD",
       "--revision",
       "src/third_party/WebKit@HEAD",
       "--revision",
       "src/v8@20123",
       "--force"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"did_run\": true, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"patch_failure\": false, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"patch_root\": \"src\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"properties\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_cr_revision\": \"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_cr_revision_cp\": \"refs/heads/master@{#170242}\", @@@",
@@ skipping 26 matching lines @@
       "@@@SET_BUILD_PROPERTY@got_webrtc_revision_cp@\"refs/heads/master@{#120644}\"@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_DEFINES": "component=static_library gomadir='[BUILD]/goma' target_arch=x64 use_goma=1"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/compile.py",
       "--target",
       "Release",
       "--src-dir",
       "[SLAVE_BUILD]/src",
       "--build-tool",
       "ninja",
       "--compiler",
       "goma",
       "--goma-dir",
       "[BUILD]/goma",
       "--",
       "blink_tests"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "compile"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--xvfb",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"V8-Blink Linux 64\", \"buildnumber\": 571, \"mastername\": \"client.v8\", \"recipe\": \"blink_downstream\", \"revision\": \"20123\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"V8-Blink Linux 64\", \"buildnumber\": 571, \"mastername\": \"client.v8\", \"recipe\": \"blink_downstream\", \"revision\": \"20123\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--builder-name=V8-Blink Linux 64",
       "--slave-name=TestSlavename",
       "--build-number=571",
       "webkit_unit_tests"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "webkit_unit_tests"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--no-xvfb",
@@ skipping 15 matching lines @@
       "--json-test-results",
       "/path/to/tmp/json",
       "--test-results-server",
       "test-results.appspot.com",
       "--build-number",
       "571",
       "--builder-name",
       "V8-Blink Linux 64",
       "--no-pixel-tests"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "webkit_tests (with patch)",
     "~followup_annotations": [
       "step returned non-zero exit code: 255",
       "@@@STEP_TEXT@<br/>unexpected_flakes:<br/>flake/slow.html<br/>flake/totally-flakey.html<br/>flake/timeout-then-crash.html<br/><br/>unexpected_failures:<br/>bad/totally-bad-probably.html<br/>tricky/totally-maybe-not-awesome.html<br/><br/>Total executed: 9001<br/>@@@",
       "@@@STEP_FAILURE@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/chromium/archive_layout_test_results.py",
       "--results-dir",
       "[SLAVE_BUILD]/layout-test-results",
       "--build-dir",
       "[SLAVE_BUILD]/src/out",
       "--build-number",
       "571",
       "--builder-name",
       "V8-Blink Linux 64",
       "--gs-bucket",
       "gs://chromium-layout-test-archives",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"V8-Blink Linux 64\", \"buildnumber\": 571, \"mastername\": \"client.v8\", \"recipe\": \"blink_downstream\", \"revision\": \"20123\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"V8-Blink Linux 64\", \"buildnumber\": 571, \"mastername\": \"client.v8\", \"recipe\": \"blink_downstream\", \"revision\": \"20123\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "archive_webkit_tests_results",
     "~followup_annotations": [
       "@@@STEP_LINK@layout_test_results@https://storage.googleapis.com/chromium-layout-test-archives/V8-Blink_Linux_64/571/layout-test-results/results.html@@@",
       "@@@STEP_LINK@(zip)@https://storage.googleapis.com/chromium-layout-test-archives/V8-Blink_Linux_64/571/layout-test-results.zip@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "import sys; sys.exit(1)"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "webkit_tests",
     "~followup_annotations": [
       "step returned non-zero exit code: 1",
       "@@@STEP_TEXT@TEST RESULTS WERE INVALID@@@",
       "@@@STEP_FAILURE@@@"
     ]
   },
   {
     "name": "$final_result",
     "reason": "1 out of 2 aggregated steps failed. Failures: Step('webkit_tests') failed with return_code 1",
     "status_code": 1
   }
 ]