* Moved the default BinaryMessenger instance to ServicesBinding

This reverts commit 821602ae.

* Added assertion in defaultBinaryMessenger. Also fixed the devicelab tests.

* Add a test for a directory instead of a single test.

* Add test data to a child directory to test the command.

* Add test data to a child directory to test the command.

* Add test data to a child directory to test the command.

* Correct test.

This reverts commit 92ef2b9c.

This requires either runApp() or
WidgetsFlutterBinding.ensureInitialized() to have been called before
using any MethodChannels. Plugins broadly rely on MethodChannels and
right now there's no general requirements that they be constructed
within the runApp call, so the ecosystem breakages from this are broader
than originally thought. Reverting for now.

- Splits on{Enter,Hover,Exit} from Listener to MouseRegion. Deprecated API is kept for compatibility.
- Splits on{Enter,Hover,Exit} from RenderPointerListener to RenderMouseRegion.

Rendering errors with root causes in the widget layer should have a reference to the widget (#32511)

* Deprecates `BinaryMessages` in favor of a default instance of `BinaryMessenger`, called `defaultBinaryMessenger`
* Platform channels use the `defaultBinaryMessenger` for their binaryMessenger default argument.

Make FlutterError objects more structured so they can be displayed better in debugging tools such as Dart DevTools.

This reverts commit 71e9bd6f.

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

* Upgrade everything except matcher.
* Roll matcher (and test)
* Adjust tests that depend on flutter:test directly to depend on a shim
* Require use of package:test shim and remove other references to package:test

* Roll the engine.

This engine includes a VM that defaults to sync-async.

flutter/engine@c8eeee4 Roll the Dart VM.

Now that we have thousands of tests, it doesn't make sense to display a separate line for each test. The result is just megabytes of logs that you have to scrub through to find error messages.

Enable --sync-async in Flutter.
Fixes #16801 

This reverts commit 39d7f22a.

This reverts commit b0b2c007.

* Turn support for sync-async on in Flutter. With this feature
execution of async functions starts immediately instead of it
being delayed by one microtask tick.

* Address review comments.

* Adjust some stack trace expectations which are slightly different with
--sync-async turned on.

Eliminates the assumption that the flutter SDK is installed in a
directory named "flutter" from ticker_expectation.txt.

* Ignore extraneous error messages outside of one skipped test

* Fix analysis error

...instead of the engine.

Also:

 * Provide a better message when you lerp from infinity to finity
   constraints.

 * Make the striped marker support RTL.

 * By popular demand, dump a warning to the console the first time
   a particular Flex overflows. (Resets on hot reload.)

Also, add tests to verify that our coverage is actually being tested!

This adds a way to run only a subset of the tests.
(The new flags do the same thing as 'pub run test'.)

* Fix tests to use Ahem, and helpful changes around that

- Fix fonts that had metric-specific behaviours.

- LiveTestWidgetsFlutterBinding.allowAllFrames has been renamed
  to LiveTestWidgetsFlutterBinding.framePolicy.

- LiveTestWidgetsFlutterBinding now defaults to using a frame policy
  that pumps slightly more frames, to animate the pointer crosshairs.

- Added "flutter run --use-test-fonts" to enable Ahem on devices.

- Changed how idle() works to be more effective in live mode.

- Display the test name in live mode (unless ahem fonts are enabled).

- Added a toString to TextSelectionPoint.

- Style nit fixes.

* Roll engine to get Ahem changes.

* Update tests for dartdoc changes.

* Fix flutter_tools tests

Aggressively apply the const lint.

...and fix bugs that the tests uncovered.

WRITE TEST FIND BUG

These tests would fail sometimes when run locally. Since they happen
to also be the ones that are flaky on bots, maybe there's some
relationship, even though the failure mode on bots is different. In
any case, this removes a variable.