Make recipes use the new way of enabling goma.

scripts/slave/recipes/dart/dartium.expected/basic_mac_64_MirrorTrue.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "config",
       "--spec",
       "cache_dir = None\nsolutions = [{'custom_vars': {'dartium_base': 'svn://svn-mirror.golo.chromium.org', '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': 'dartium.deps', 'url': 'svn://svn-mirror.golo.chromium.org/dart/branches/bleeding_edge/deps/dartium.deps'}]"
     ],
@@ skipping 49 matching lines @@
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "env": {
-      "GYP_DEFINES": "clang=1 component=static_library linux_strip_binary=1 target_arch=x64",
+      "GYP_DEFINES": "clang=1 component=static_library gomadir=[BUILD]/goma linux_strip_binary=1 target_arch=x64 use_goma=1",
       "GYP_GENERATORS": "ninja"
     },
     "name": "gclient runhooks"
   },
   {
     "abort_on_failure": true,
     "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",
       "--",
       "All",
       "chromium_builder_tests"
     ],
     "name": "compile"
   },
   {
     "always_run": true,
     "cmd": [
       "python",
@@ skipping 10 matching lines @@
       "--target",
       "Release",
       "-o",
       "[SLAVE_BUILD]/layout-test-results",
       "--build-dir",
       "[SLAVE_BUILD]/src/out"
     ],
     "name": "webkit_tests"
   }
 ]