Make download_from_google_storage print less during runhooks.

DEPS

 # This file contains dependencies for WebRTC that are not shared with Chromium.
 # If you wish to add a dependency that is present in Chromium's src/DEPS or a
 # directory from the Chromium checkout, you should add it to setup_links.py
 # instead.
 
 vars = {
   'extra_gyp_flag': '-Dextra_gyp_flag=0',
   'chromium_git': 'https://chromium.googlesource.com',
   'chromium_revision': '53970fd73572a0ca98a89820bb98b7ad3f583ca3',
 }
@@ skipping 84 matching lines @@
      'action': ['python', 'src/third_party/instrumented_libraries/scripts/download_binaries.py'],
    },
   {
     # Download test resources, i.e. video and audio files from Google Storage.
     'pattern': '.',
     'action': ['download_from_google_storage',
                '--directory',
                '--recursive',
                '--num_threads=10',
                '--no_auth',
+               '--quiet',
                '--bucket', 'chromium-webrtc-resources',
                'src/resources'],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     'name': 'gyp',
     'pattern': '.',
     'action': ['python', 'src/webrtc/build/gyp_webrtc',
                Var('extra_gyp_flag')],
   },
 ]