b6b54fd60 PR (#45456)

git@github.com:flutter/engine.git/compare/591144dfef59...b6b54fd60631

git log 591144dfef59..b6b54fd60631 --no-merges --oneline
2019-11-23 chinmaygarde@google.com PR


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC aaclarke@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md