WebRTC: Add Linux32 ARM builder.

scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_fyi_linux32_arm.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
-      "tryserver.webrtc",
+      "client.webrtc.fyi",
       "--builder",
-      "linux_compile_rel",
+      "Linux32 ARM",
       "--slave",
       "slavename",
       "--spec",
       "cache_dir = None\nsolutions = [{'deps_file': 'DEPS', 'managed': True, 'name': 'src', 'url': 'https://chromium.googlesource.com/external/webrtc'}, {'deps_file': 'DEPS', 'managed': True, 'name': 'webrtc-limited', 'url': 'https://chrome-internal.googlesource.com/chrome/deps/webrtc-limited'}]",
       "--root",
       "src",
       "--revision_mapping_file",
       "{\"src\": \"got_revision\"}",
-      "--issue",
-      "666666",
-      "--patchset",
-      "1",
-      "--rietveld_server",
-      "https://fake.rietveld.url",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
       "src@12345",
       "--output_manifest"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
@@ skipping 40 matching lines @@
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
-      "GYP_DEFINES": "component=static_library dcheck_always_on=1 fastbuild=1 gomadir='[BUILD]/goma' target_arch=x64 use_goma=1"
+      "GYP_CROSSCOMPILE": "1",
+      "GYP_DEFINES": "component=static_library dcheck_always_on=1 gomadir='[BUILD]/goma' target_arch=arm use_goma=1"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/compile.py",
       "--target",
       "Release",
       "--src-dir",
       "[SLAVE_BUILD]/src",
       "--build-tool",
       "ninja",
       "--compiler",
       "goma",
       "--goma-dir",
       "[BUILD]/goma",
-      "--goma-fail-fast",
-      "--goma-disable-local-fallback",
       "--",
       "All"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "compile"
   }
 ]