WebRTC: Enable MB for Android bots.

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

Index: scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_android_rel.json
diff --git a/scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_android_rel.json b/scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_android_rel.json
index d2b004c2c5d1dda1e15cbf49e371cfa9cae1a0fb..2fe2362c26080e26b8df03b0c8d69614d05ddfe9 100644
--- a/scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_android_rel.json
+++ b/scripts/slave/recipes/webrtc/standalone.expected/tryserver_webrtc_android_rel.json
@@ -184,6 +184,7 @@
     "cwd": "[BUILDER_CACHE]/android_rel/src",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
+      "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_CROSSCOMPILE": "1",
       "GYP_DEFINES": "OS=android component=static_library dcheck_always_on=1 fastbuild=1 gomadir='[CACHE]/cipd/goma' target_arch=arm use_goma=1",
       "PATH": "[BUILDER_CACHE]/android_rel/src/third_party/android_tools/sdk/platform-tools:[BUILDER_CACHE]/android_rel/src/build/android:%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
@@ -194,6 +195,29 @@
     "cmd": [
       "python",
       "-u",
+      "[BUILDER_CACHE]/android_rel/src/tools/mb/mb.py",
+      "gen",
+      "-m",
+      "tryserver.webrtc",
+      "-b",
+      "android_rel",
+      "--config-file",
+      "[BUILDER_CACHE]/android_rel/src/webrtc/build/mb_config.pyl",
+      "--goma-dir",
+      "[CACHE]/cipd/goma",
+      "--gyp-script=[BUILDER_CACHE]/android_rel/src/webrtc/build/gyp_webrtc.py",
+      "//out/Release"
+    ],
+    "cwd": "[BUILDER_CACHE]/android_rel/src",
+    "env": {
+      "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
+    },
+    "name": "generate_build_files"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/tools/runit.py",
       "--show-path",
       "python",