This reverts commit 35ad43f2.

This reverts commit c26ed03c.

* Migrate to ChannelBuffers.push

* Move TestDefaultBinaryMessenger to its own file

* Apply deprecations and fix usages

* Add semantics sort key for modal scope and modal barrier

* fix test

* fix test

* fix test

* fix space

* fix more tests

* addressing comments

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag

* replace simple Container(w & h) with SizedBox

* address review comments

* address review comments

* 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

* Fix Tooltip Directionality

* Add regression test comment for tooltip directionality fix

* add missing trailing commas

* add more missing trailing commas

* add more and more missing trailing commas

* Add DefaultTextStyle parent widget to Tooltip Overlay

* Add test against fallback DefaultTextStyle

Guard removePointer with addTearDown to avoid cascading test crash.

* Add margin parameter to tooltips

* Improve tooltip tests to find the tooltip's `Container` instead of arbitrary number of parent calls

* Improve showDuration and waitDuration explanation and tests

* Add condition to test to ensure that tooltip does not show before long press duration is over

* Implement TooltipThemeData and TooltipTheme

* Add text style property 

* Updated tooltip default colors for light and dark theme to match Material specification

Revert "[Material] Implement TooltipTheme and Tooltip.textStyle, fix Tooltip debugLabel, update Tooltip defaults (#36030)" (#36851)

This reverts commit 62158a1b.

[Material] Implement TooltipTheme and Tooltip.textStyle, fix Tooltip debugLabel, update Tooltip defaults (#36030)

* Implement TooltipThemeData and TooltipTheme

* Add tooltip text style property

* Update default tooltip text style and decoration to match Material specification

* Fix debugLabel incorrectly labeling "white" as "black", and vice versa by default

This is a re-land of #31561, after fixing performance regressions.

Added change listening to the MouseTracker so that the Listener and tooltip can react to whether or not a mouse is connected at all. Added a change check to make sure Listener only repaints when something changed.

Fixes #22817