Recipes: make cwd default to slave_build

scripts/slave/recipes/webrtc/chromium.expected/chromium_webrtc_fyi_Mac_Builder.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.webrtc.fyi",
       "--builder",
       "Mac 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'}, {'deps_file': 'DEPS', 'managed': True, 'name': 'webrtc.DEPS', 'url': 'https://chromium.googlesource.com/chromium/deps/webrtc/webrtc.DEPS'}]",
       "--root",
       "src",
       "--revision_mapping_file",
       "{\"src\": \"got_revision\", \"src/native_client\": \"got_nacl_revision\", \"src/third_party/WebKit\": \"got_webkit_revision\", \"src/third_party/libjingle/source/talk\": \"got_libjingle_revision\", \"src/third_party/libvpx/source\": \"got_libvpx_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",
       "--revision",
       "src@HEAD",
       "--revision",
       "src/third_party/libjingle/source/talk@HEAD",
       "--revision",
       "src/third_party/webrtc@HEAD"
     ],
+    "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_libjingle_revision\": \"8e938c8836c7ed23d7fbcddf1dcc2abcb13667d7\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"got_libjingle_revision_cp\": \"refs/heads/master@{#134440}\", @@@",
@@ skipping 34 matching lines @@
       "@@@SET_BUILD_PROPERTY@got_libjingle_revision_cp@\"refs/heads/master@{#134440}\"@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[webrtc]/resources/cleanup_files.py",
       "[SLAVE_BUILD]/src/out"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "clean test output files"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/cleanup_temp.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "cleanup_temp"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_DEFINES": "blink_logging_always_on=1 clang=1 component=static_library dcheck_always_on=1 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-clang",
       "--goma-dir",
       "[BUILD]/goma",
       "--",
       "chromium_builder_webrtc"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "compile"
   },
   {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
@@ skipping 12 matching lines @@
       "--slave-name=TestSlavename",
       "--build-number=571",
       "--run-python-script",
       "--revision=f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
       "[BUILD]/scripts/slave/chromium/sizes.py",
       "--target",
       "Release",
       "--platform",
       "mac"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "sizes"
   },
   {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/zip_build.py",
       "--target",
       "Release",
       "--build-url",
       "gs://chromium-webrtc/mac_rel-fyi",
       "--build_revision",
       "f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"Mac Builder\", \"buildnumber\": 571, \"got_libjingle_revision\": \"1161aa63\", \"got_revision\": \"c321321\", \"got_webrtc_revision\": \"deadbeef\", \"mastername\": \"chromium.webrtc.fyi\", \"parent_buildername\": null, \"recipe\": \"webrtc/chromium\", \"revision\": \"deadbeef\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"buildername\": \"Mac Builder\", \"buildnumber\": 571, \"got_libjingle_revision\": \"1161aa63\", \"got_revision\": \"c321321\", \"got_webrtc_revision\": \"deadbeef\", \"mastername\": \"chromium.webrtc.fyi\", \"parent_buildername\": null, \"recipe\": \"webrtc/chromium\", \"revision\": \"deadbeef\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "package build"
   },
   {
     "cmd": [],
+    "cwd": "[SLAVE_BUILD]",
     "name": "trigger",
     "trigger_specs": [
       {
         "builder_name": "Mac Tester",
         "properties": {
           "parent_got_libjingle_revision": "8e938c8836c7ed23d7fbcddf1dcc2abcb13667d7",
           "parent_got_libjingle_revision_cp": "refs/heads/master@{#134440}",
           "parent_got_revision": "f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
           "parent_got_revision_cp": "refs/heads/master@{#170242}",
           "parent_got_webrtc_revision": "0f90628433546e61d9268596da93418c623137f4",
           "parent_got_webrtc_revision_cp": "refs/heads/master@{#120644}",
           "revision": "f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9"
         }
       }
     ],
     "~followup_annotations": [
       "@@@STEP_TEXT@Mac Tester@@@"
     ]
   }
 ]