git@github.com:flutter/engine.git/compare/7d8c6d9c1a5c...e12decfdd210

git log 7d8c6d9c1a5c..e12decfdd210 --no-merges --oneline
2019-09-13 xster@google.com Clean up after AppLifecycleTests (flutter/engine#12273)
2019-09-13 dnfield@google.com Close the tree (flutter/engine#12268)


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 jimgraham@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