Add counting the number of CPU's in goma module

scripts/slave/recipes/chromium.expected/full_chromium_chromiumos_ChromiumOS_x86_generic_Compile.json

 [
   {
     "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",
       "[BUILDER_CACHE]/ChromiumOS_x86_generic_Compile",
       "511"
     ],
     "name": "makedirs checkout path",
@@ skipping 171 matching lines @@
       "@@@STEP_LOG_LINE@json.output@      \"instance_id\": \"resolved-instance_id-of-release---------\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"package\": \"infra_internal/goma/client/linux-amd64\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }@@@",
       "@@@STEP_LOG_LINE@json.output@  ]@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
+      "python",
+      "-u",
+      "\nimport multiprocessing\n\ntry:\n  jobs = min(200, multiprocessing.cpu_count() * 10)\nexcept NotImplementedError:\n  jobs = 50\n\nprint jobs\n"
+    ],
+    "name": "ensure_goma.get the number of cpus",
+    "stdout": "/path/to/tmp/",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import multiprocessing@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@try:@@@",
+      "@@@STEP_LOG_LINE@python.inline@  jobs = min(200, multiprocessing.cpu_count() * 10)@@@",
+      "@@@STEP_LOG_LINE@python.inline@except NotImplementedError:@@@",
+      "@@@STEP_LOG_LINE@python.inline@  jobs = 50@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@print jobs@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
+    "cmd": [
       "RECIPE_PACKAGE_REPO[depot_tools]/cros",
       "chrome-sdk",
       "--board=x86-generic",
       "--nocolor",
       "--use-external-config",
       "--clear-sdk-cache",
       "--gomadir",
       "[CACHE]/cipd/goma",
       "--",
       "python",
@@ skipping 171 matching lines @@
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"build_data_dir\": \"[ROOT]/build_data_dir\", \"buildername\": \"ChromiumOS x86-generic Compile\", \"buildnumber\": 571, \"mastername\": \"chromium.chromiumos\", \"parent_buildername\": null, \"path_config\": \"kitchen\", \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
     "name": "package build"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]