* 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 PR adds TargetPlatform.macOS to the TargetPlatform enum. This allows us to begin implementation of some adaptive UI based on which target platform is desired.

I haven't updated the tests here, that will come in a follow-up PR.

No code changes, just comments: I spell-checked all the comments in the repo.

* make BuildContext.{ancestorStateOfType,ancestorRenderObjectOfType,rootAncestorStateOfType} generic

* make BuildContext.inheritFromWidgetOfExactType generic

* make BuildContext.ancestorInheritedElementForWidgetOfExactType generic

* make BuildContext.ancestorWidgetOfExactType generic

* fix snippet

* bump scoped_model on temp version

* update names

* Revert "bump scoped_model on temp version"

This reverts commit d1fcbba028cdb07f44738d1652391692d1ea5ec0.

* address review comments

* fix ci

* address review comments

* repeat the deprecation notice

* fix uppercase

* use of recommanded deprecation syntax

* address review comment

This fixes the sample code analysis to treat dartpad snippets in the same way as snippet snippets, which it wasn't until now (the snippet generator was treating them as "samples"), and some errors crept in. This PR also fixes those errors.

Also, added a --verbose option to the sample analyzer.

Adds the CupertinoContextMenu widget for iOS 13 support.

Fixes #42049.

Drag from the right is no more
Longpress is now only 100ms instead of 500
Added optional duration field to longpressgesturerecognizer
Added controller field to material scrollbar api
Haptic feedback only triggers when scrollbar is fully expanded
Added haptic feedback when releasing the scrollbar after dragging it

This flag controls Android's keyboard suggestions on/off

* Add structured errors in Animations, TabView, ChangeNotifier

* Add structured error on MaterialPageRoute, BoxBorder, DecorationImagePainter, TextSpan

* Add structured errors in Debug

* Fix test errors

* Add structured errors in Scaffold and Stepper

* Add structured errors in part of Rendering Layer

* Fix failing test due to FloatingPoint precision

* Fix failing tests due to precision error and not using final

* Fix failing test due to floating precision error with RegEx instead

* Add structured error in CustomLayout and increase test coverage

* Add structured error & its test in ListBody

* Add structured error in ProxyBox and increase test coverage

* Add structured error message in Viewport

* Fix styles and add more assertions on ErrorHint and DiagnosticProperty

* Add structured error in scheduler/binding and scheduler/ticker
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Add structured error in AssetBundle and TextInput
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Add structured errors in several widgets #1
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Remove unused import
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Add assertions on hint messages
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Fix catch spacing
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Add structured error in several widgets part 2 and increase code coverage
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Add structured error in flutter_test/widget_tester

* Fix floating precision accuracy by using RegExp
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Remove todo to add tests in Scaffold showBottomSheet
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Fix reviews by indenting lines and fixing the assertion orders
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Fix failing tests due to renaming class
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Try skipping the NetworkBundleTest
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

* Remove leading space in material/debug error hint
Signed-off-by: Albertus Angga Raharja <albertusangga@google.com>

Use assertions to prevent multiline password fields from being created

In #42533, I disabled the up/down arrows for focus navigation in text fields, but we thought of a better way to do it, so this is that better way.

This change reverts the other change, and instead it tests the context of the node in the action to see if it's an EditableText node. If so, then it doesn't do the navigation action.

This disables the arrow key focus navigation for text fields. This was non-standard behavior for text fields, although it remains useful for other kinds of controls.

Fixes #42259

This attempts to reland #40186 and #41220, that were reverted in #41945.

The main modifications from the original PRs are that I predefine the shortcuts and actions maps instead of defining them inline in the build function, and I use a new mapEquals to do a deep comparison so that we don't rebuild modified things if the contents of the map haven't changed.

I also eliminated an operator== and hashCode that were defined on the Actions widget, since widgets shouldn't have those. (it's too bad though: I get an 85% speedup if we leave this in! Too bad it prevents rebuilding of the children...)

Fixes #40101

* add missing trailing commas

* add more missing trailing commas

* add more and more missing trailing commas