Recipes: make cwd default to slave_build

scripts/slave/recipe_modules/android/example.expected/basic.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.linux",
       "--builder",
       "Android Builder",
       "--slave",
       "totallyanandroid-m1",
       "--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'}]\ntarget_os = ['android']",
       "--root",
       "src",
       "--revision_mapping_file",
       "{}",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@123456"
     ],
+    "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@  \"root\": \"src\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"step_text\": \"Some step text\"@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_CHROMIUM_NO_ACTION": "1"
     },
     "name": "gclient runhooks"
   },
   {
     "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",
       "[SLAVE_BUILD]/android-src",
       "511"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "makedirs android source root",
     "~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)@@@",
@@ skipping 25 matching lines @@
     "name": "repo sync"
   },
   {
     "cmd": [
       "[BUILD]/scripts/slave/android/with_lunch",
       "[SLAVE_BUILD]/android-src",
       "nakasi-userdebug",
       "RECIPE_MODULE[android]/resources/update_default_props.py",
       "ro.adb.secure=0"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "update /root/default.prop"
   },
   {
     "cmd": [
       "[SLAVE_BUILD]/src/android_webview/buildbot/deps_whitelist.py",
       "--method",
       "android_rsync_build",
       "--path-to-deps",
       "[SLAVE_BUILD]/src/DEPS",
       "--output-json",
       "/path/to/tmp/json"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "calculate blacklist",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"blacklist\": [@@@",
       "@@@STEP_LOG_LINE@json.output@    \"blacklist/project/1\", @@@",
       "@@@STEP_LOG_LINE@json.output@    \"blacklist/project/2\"@@@",
       "@@@STEP_LOG_LINE@json.output@  ]@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "rsync",
       "-rav",
       "--delete",
       "--delete-excluded",
       "--exclude=.svn",
       "--exclude=.git",
       "--exclude=blacklist/project/1",
       "--exclude=blacklist/project/2",
       "[SLAVE_BUILD]/src/",
       "[SLAVE_BUILD]/android-src/external/chromium_org"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "rsync chromium_org"
   },
   {
     "cmd": [
       "[BUILD]/scripts/slave/android/with_lunch",
       "[SLAVE_BUILD]/android-src",
       "nakasi-userdebug",
       "[BUILD]/scripts/slave/compile.py",
       "CC=foo CXX=bar",
       "droid",
       "--build-dir",
       "[SLAVE_BUILD]",
       "--src-dir",
       "[SLAVE_BUILD]/android-src",
       "--build-tool",
       "make-android",
       "--verbose"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "compile android"
   }
 ]