--- a/testing/mochitest/runtests.py
+++ b/testing/mochitest/runtests.py
@@ -85,17 +85,16 @@ here = os.path.abspath(os.path.dirname(_
 ########################################
 
 # Set the desired log modules you want a log be produced
 # by a try run for, or leave blank to disable the feature.
 # This will be passed to MOZ_LOG environment variable.
 # Try run will then put a download link for all log files
 # on tbpl.mozilla.org.
 
-# MOZ_LOG = "signaling:3,mtransport:4,DataChannel:4,jsep:4,MediaPipelineFactory:4"
 MOZ_LOG = ""
 
 #####################
 # Test log handling #
 #####################
 
 # output processing
 
@@ -766,17 +765,17 @@ class MochitestDesktop(object):
     sslTunnel = None
     DEFAULT_TIMEOUT = 60.0
     mediaDevices = None
 
     # XXX use automation.py for test name to avoid breaking legacy
     # TODO: replace this with 'runtests.py' or 'mochitest' or the like
     test_name = 'automation.py'
 
-    def __init__(self, logger_options):
+    def __init__(self, logger_options, quiet=False):
         self.update_mozinfo()
         self.server = None
         self.wsserver = None
         self.websocketProcessBridge = None
         self.sslTunnel = None
         self._active_tests = None
         self._locations = None
 
@@ -792,17 +791,17 @@ class MochitestDesktop(object):
                 "Mochitest specific tbpl formatter")
             self.log = commandline.setup_logging("mochitest",
                                                  logger_options,
                                                  {
                                                      "tbpl": sys.stdout
                                                  })
             MochitestDesktop.log = self.log
 
-        self.message_logger = MessageLogger(logger=self.log)
+        self.message_logger = MessageLogger(logger=self.log, buffering=quiet)
         # Max time in seconds to wait for server startup before tests will fail -- if
         # this seems big, it's mostly for debug machines where cold startup
         # (particularly after a build) takes forever.
         self.SERVER_STARTUP_TIMEOUT = 180 if mozinfo.info.get('debug') else 90
 
         # metro browser sub process id
         self.browserProcessId = None
 
@@ -1868,27 +1867,22 @@ toolbar#nav-bar {
                valgrindPath=None,
                valgrindArgs=None,
                valgrindSuppFiles=None,
                symbolsPath=None,
                timeout=-1,
                detectShutdownLeaks=False,
                screenshotOnFail=False,
                bisectChunk=None,
-               quiet=False,
                marionette_args=None):
         """
         Run the app, log the duration it took to execute, return the status code.
         Kills the app if it runs for longer than |maxTime| seconds, or outputs nothing
         for |timeout| seconds.
         """
-
-        # configure the message logger buffering
-        self.message_logger.buffering = quiet
-
         # It can't be the case that both a with-debugger and an
         # on-Valgrind run have been requested.  doTests() should have
         # already excluded this possibility.
         assert not(valgrindPath and debuggerInfo)
 
         # debugger information
         interactive = False
         debug_args = None
@@ -2391,17 +2385,16 @@ toolbar#nav-bar {
                                  valgrindPath=valgrindPath,
                                  valgrindArgs=valgrindArgs,
                                  valgrindSuppFiles=valgrindSuppFiles,
                                  symbolsPath=options.symbolsPath,
                                  timeout=timeout,
                                  detectShutdownLeaks=detectShutdownLeaks,
                                  screenshotOnFail=options.screenshotOnFail,
                                  bisectChunk=options.bisectChunk,
-                                 quiet=options.quiet,
                                  marionette_args=marionette_args,
                                  )
         except KeyboardInterrupt:
             self.log.info("runtests.py | Received keyboard interrupt.\n")
             status = -1
         except:
             traceback.print_exc()
             self.log.error(
@@ -2655,17 +2648,17 @@ toolbar#nav-bar {
 
 def run_test_harness(parser, options):
     parser.validate(options)
 
     logger_options = {
         key: value for key, value in vars(options).iteritems()
         if key.startswith('log') or key == 'valgrind'}
 
-    runner = MochitestDesktop(logger_options)
+    runner = MochitestDesktop(logger_options, quiet=options.quiet)
 
     options.runByDir = False
 
     if options.flavor in ('plain', 'browser', 'chrome'):
         options.runByDir = True
 
     result = runner.runTests(options)
 

--- a/testing/mochitest/runtestsremote.py
+++ b/testing/mochitest/runtestsremote.py
@@ -282,17 +282,16 @@ class MochiRemote(MochitestDesktop):
 
         # automation.py/remoteautomation `runApp` takes the profile path,
         # whereas runtest.py's `runApp` takes a mozprofile object.
         if 'profileDir' not in kwargs and 'profile' in kwargs:
             kwargs['profileDir'] = kwargs.pop('profile').profile
 
         # remove args not supported by automation.py
         kwargs.pop('marionette_args', None)
-        kwargs.pop('quiet', None)
 
         return self._automation.runApp(*args, **kwargs)
 
 
 def run_test_harness(parser, options):
     parser.validate(options)
 
     message_logger = MessageLogger(logger=None)