* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

This fixes https://github.com/flutter/flutter/issues/39277

The following tests cover this change:
- packages/flutter/test/foundation/service_extensions_test.dart
- packages/flutter/test/scheduler/scheduler_test.dart

This reverts commit 6ef80b44.

This is the continuation of https://github.com/flutter/engine/pull/11041 and https://github.com/flutter/flutter/pull/38574

This is not a breaking change as we're not removing `onReportTimings` API.
We're simply removing the use of it in our framework.

Filed: https://github.com/flutter/flutter/issues/38838
to track these usages.

This was introduced by: https://github.com/flutter/engine/pull/11041

Revert "Revert "redux of a change to use new engine APIs for Flutter.Frame events (#34365)" (#34514)" (#34530)

This reverts commit 8f75d537.

This reverts commit ceb09b8b.

This reverts commit 446179f6.

* update the Flutter.Frame event to use new engine APIs

* add a test

* update test

This reverts commit ab707aca.

Revert "Add currentSystemFrameTimeStamp to SchedulerBinding (#33886)"

This reverts commit 61b83d32.

Convert scheduling to use `scheduleMicrotask` instead of `Timer.run`

* 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

* Lock events during runApp's warm up frame

* move to scheduler binding

* let the one scheduleWarmUpFrame api always lock

* tweak test

* Add more checks to scheduleWarmUpFrame

* review

* add test

...instead of the engine.

* enable lint prefer_foreach

* fix tests

The old names were getting silly and started stepping on valuable namespace.

The new names are consistent and clear.

We're getting back to the point where we have a bunch of foundation APIs
and it's getting confusing having them mixed with services/.

This test is no longer disabled.

Fixes #2827

Well, all the easy ones, anyway.

For some reason `// ignore:` isn't working for me so I've disabled
lints that need that. Also disabled those that require a ton of work
(which I'm doing, but not in this PR, to keep it reviewable).

This adds:
- avoid_init_to_null
- library_names
- package_api_docs
- package_names
- package_prefixed_library_names
- prefer_is_not_empty
- sort_constructors_first
- sort_unnamed_constructors_first
- unnecessary_getters_setters

This is a workaround for:
   https://github.com/dart-lang/sdk/issues/25246

The names are probably less familiar, but more consistent:
- FrameCallback: a callback that is relative to the frame and wants the
  frame offset (a duration) as argument.
- addXFrameCallback: adds the given callback to the internal lists/maps.
- scheduleXFrameCallback (currently only X = ""): add the callback, but
  also trigger a new frame.
- handleX: the method that is invoked when the event-loop or the frame
  calls into the scheduler.
- ensureXYZ: ensure that the callback happens.
  Unfortunately there is the ambiguity between a "callback": it can be a
  closure, or the action of doing a callback, so we end up with:
  ensureBeginFrameCallback, and ensureEventLoopCallback, where
  "callback" means the action of being called back.

The current implementation is still pretty rudimentary.