Fixes a precision bug was introduced in 784e6d74, which improved the
precision of lerpDouble when the extrema differed significantly in
magnitude.

_lerpInt doesn't have this issue since the extrema are passed as 64-bit
twos-complement values, therefore the difference will always be accurate
so long as it doesn't overflow. This reverts the _lerpInt implementation
to the original a + (b - a) * t, but adds a test to avoid a regression
if anyone is tempted to make it consistent with the others.

This reverts commit cde78c16.

* Revert "Roll Dart SDK from 9f907e198970 to 37ccceacad41 (3 revisions) (#22069)"

This reverts commit 4f4599b2.

* Revert "Roll Dart SDK from a3d902d8598e to 9f907e198970 (2 revisions) (#22058)"

This reverts commit e51c710e.

* support uri intent launcher in android

* fix comment

Initialize the AssetManager from the application context so that assets from dynamic feature modules can be loaded.

Related to https://github.com/flutter/flutter/issues/65270

This re-lands #20496 and #21780 after fixing the semantics-enabling code that was causing the post-submit web_smoke_test to fail.

Below is the description from the original PR:

This is a PR for converting the dart:ui code in the engine to use a multi-window API. The goal here is to convert from the window singleton to an API that has the concept of multiple windows. Also, I'm matching up the new PlatformDispatcher class to talk directly to the PlatformConfiguration class in the engine. I'm not attempting to actually enable creating multiple windows here, just migrate to an API that has a concept of multiple windows. The multi-window API in this PR currently only ever creates one window.

The design doc for this change is here.

The major changes in this PR:

Move the platfom-specific attributes out of Window, and into the new PlatformDispatcher class that holds all of the platform state, so that the platform code need only update the configuration on this class.
Create FlutterView, FlutterWindow, and SingletonFlutterWindow classes to separate out the concepts of a view (of which there may be multiple in a window), a window (of which there may be multiple on a screen, and they host views), and a window where there is only ever expected to be one (this hosts the entire API of the former Window class, and will eventually be the type of the window singleton).
Next step after this PR lands:

Remove the Window class entirely (it is replaced by SingletonFlutterWindow). Some minor changes in the Framework are needed to switch to using SingletonFlutterWindow directly first.

The Window class still exists in this PR, but will be removed as soon as the framework is converted to point to the SingletonFlutterWindow class instead. They share the same API, just have different names (Window is currently a subclass of SingletonFlutterWindow). The intention is that the Window name will be freed up to use as a widget class name in the framework for managing windows. The singleton called window will remain, and keep the same API it has now.

This reverts commit d2ea378b.

https://skia.googlesource.com/skia.git/+log/5c7bb326a7b3..65674e4c2e56

2020-10-22 kjlubick@google.com [canvaskit] Compile in most gms for testing
2020-10-22 johnstiles@google.com Reland "Add pooling support on iOS."
2020-10-22 egdaniel@google.com Fix asserts for npot tiling in gl.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC egdaniel@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

* Reland fuchsia external view embedder will be shared with platform view

This reverts commit 9b752790.

* wait for the external view embedder to be initialized before creating
shell

https://dart.googlesource.com/sdk.git/+log/a3d902d8598e..9f907e198970

2020-10-22 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.11.0-244.0.dev
2020-10-21 dart-luci-ci-builder@dart-ci.iam.gserviceaccount.com Version 2.11.0-243.0.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

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/fuchsia-mac-sdk-flutter-engine
Please CC chinmaygarde@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

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/fuchsia-linux-sdk-flutter-engine
Please CC chinmaygarde@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