This reverts commit 2decf195.

* Implement Color filter layer
* Add test with BlendMode color
* update licenses file
* Move blend functions into color_filter.dart
* dartfmt

This reverts commit d241105d.

This reverts commit 3fe49ec3.

The behaviour of lerpDouble with respect to null inputs isn't entirely
obvious. In the case where both inputs are null, it returns null.
Otherwise, it defaults the null parameter to 0.0 and carries on.

Post non-null by default, it might be nice to strengthen the parameter
contract to require them to be non-null. While this would be a breaking
change, it seems likely that the framework either meets this guarantee
or can provide it without a framework breaking change.

https://github.com/flutter/flutter/issues/64617 tracks the above.

In the meantime, adding a test to lock in the current behaviour.

https://dart.googlesource.com/sdk.git/+log/56c106399a6c..152026d794c8

2020-08-26 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.10.0-62.0.dev
2020-08-26 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.10.0-61.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@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/+doc/master/autoroll/README.md

https://dart.googlesource.com/sdk.git/+log/551e405d0b5d..8a66cef2c42f

2020-08-26 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.10.0-59.0.dev
2020-08-25 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.10.0-58.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@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/+doc/master/autoroll/README.md

a custom version string of Dart for Flutter.

Dart is going to be removing support for this ability to generate
a custom version string (only dev branch hashes are being rolled into
flutter).

This reverts commit ceaf605a.