Enable errorprone on the chromium.fyi Errorprone Builder (Reland).

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.fyi",
       "--builder",
       "Android Builder (dbg)",
@@ skipping 49 matching lines @@
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_CROSSCOMPILE": "1",
-      "GYP_DEFINES": "OS=android component=static_library fastbuild=1 gomadir='[BUILD]/goma' target_arch=arm use_goma=1",
+      "GYP_DEFINES": "OS=android component=static_library enable_errorprone=1 fastbuild=1 gomadir='[BUILD]/goma' target_arch=arm use_goma=1",
       "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/testing/buildbot/chromium.fyi.json",
@@ skipping 209 matching lines @@
     "trigger_specs": [
       {
         "builder_name": "Android Tests (trial)(dbg)"
       }
     ],
     "~followup_annotations": [
       "@@@STEP_TEXT@Android Tests (trial)(dbg)@@@"
     ]
   }
 ]