[MDC roll] Roll Material Components to 6cee78256b6c519ab026582e369676d75fdf6878

TBR=smut

Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I3f22876932f75eaa61f61e6d5fd8183c14199caa
Reviewed-on: https://chromium-review.googlesource.com/1009362
Commit-Queue: iOS Autoroller <ios-autoroller@chromium.org>
Reviewed-by: iOS Autoroller <ios-autoroller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550073}

DEPS

@@ -224,7 +224,7 @@ deps = {
   },
 
   'src/ios/third_party/material_components_ios/src': {
-      'url': Var('chromium_git') + '/external/github.com/material-components/material-components-ios.git' + '@' + '129093a857a9bc72fc4a8869ace971ae3c39842e',
+      'url': Var('chromium_git') + '/external/github.com/material-components/material-components-ios.git' + '@' + '6cee78256b6c519ab026582e369676d75fdf6878',
       'condition': 'checkout_ios',
   },
 

ios/third_party/material_components_ios/README.chromium

 Name: Material Components for iOS
 URL: https://github.com/material-components/material-components-ios
 Version: 0
-Revision: 129093a857a9bc72fc4a8869ace971ae3c39842e
+Revision: 6cee78256b6c519ab026582e369676d75fdf6878
 License: Apache 2.0
 License File: LICENSE
 Security Critical: yes