Use MB on all of the blink bots.

scripts/slave/recipes/chromium.expected/full_chromium_webkit_WebKit_Win7.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]\\scripts\\slave\\kill_processes.py"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "taskkill"
   },
@@ skipping 104 matching lines @@
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
+      "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "chromium_win_pch=0 component=static_library fastbuild=1 gomadir='[BUILD]\\goma' target_arch=ia32 test_isolation_mode=prepare use_goma=1"
     },
     "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.webkit.json",
@@ skipping 316 matching lines @@
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "process_dumps"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]