WebRTC: Move ensure_goma step to before runhooks step.

scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_mac_gn_dbg.json

 [
   {
     "cmd": [
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/ios/host_info.py",
       "--json-file",
       "/path/to/tmp/json"
     ],
     "name": "host and tools info",
     "~followup_annotations": [
       "@@@STEP_TEXT@<br />OS X 1.2.3, Xcode 6.7.8 (5D342509a)@@@",
@@ skipping 86 matching lines @@
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/tools/runit.py",
       "--show-path",
       "python",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/cleanup_temp.py"
     ],
     "name": "cleanup_temp"
   },
   {
-    "cmd": [
-      "python",
-      "-u",
-      "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
-      "runhooks"
-    ],
-    "cwd": "[SLAVE_BUILD]/src",
-    "env": {
-      "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
-      "GYP_CHROMIUM_NO_ACTION": "1",
-      "GYP_DEFINES": "clang=1 component=shared_library dcheck_always_on=1 fastbuild=1 ffmpeg_branding=Chrome gomadir='[BUILD]/goma' rtc_use_h264=1 target_arch=x64 use_goma=1",
-      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
-    },
-    "name": "gclient runhooks"
-  },
-  {
-    "cmd": [
-      "python",
-      "-u",
-      "[DEPOT_TOOLS]/gn.py",
-      "--root=[SLAVE_BUILD]/src",
-      "gen",
-      "//out/Debug",
-      "--args=ffmpeg_branding=\"Chrome\" rtc_use_h264=true is_debug=true target_cpu=\"x64\" use_goma=true goma_dir=\"[BUILD]/goma\""
-    ],
-    "name": "gn"
-  },
-  {
     "cmd": [],
     "name": "ensure_goma"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[build::cipd]/resources/bootstrap.py",
       "--platform",
       "mac-amd64",
@@ skipping 34 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"instance_id\": \"resolved-instance_id-of-release---------\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"package\": \"infra_internal/goma/client/mac-amd64\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }@@@",
       "@@@STEP_LOG_LINE@json.output@  ]@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
+      "runhooks"
+    ],
+    "cwd": "[SLAVE_BUILD]/src",
+    "env": {
+      "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
+      "GYP_CHROMIUM_NO_ACTION": "1",
+      "GYP_DEFINES": "clang=1 component=shared_library dcheck_always_on=1 fastbuild=1 ffmpeg_branding=Chrome gomadir='[CACHE]/cipd/goma' rtc_use_h264=1 target_arch=x64 use_goma=1",
+      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "name": "gclient runhooks"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[DEPOT_TOOLS]/gn.py",
+      "--root=[SLAVE_BUILD]/src",
+      "gen",
+      "//out/Debug",
+      "--args=ffmpeg_branding=\"Chrome\" rtc_use_h264=true is_debug=true target_cpu=\"x64\" use_goma=true goma_dir=\"[CACHE]/cipd/goma\""
+    ],
+    "name": "gn"
+  },
+  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/clang_revision.py",
       "--src-dir",
       "[SLAVE_BUILD]/src",
       "--output-json",
       "/path/to/tmp/json"
     ],
@@ skipping 49 matching lines @@
       "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
       "@@@STEP_LOG_END@json.output (invalid)@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]