This normalizes all of the "See also" blocks in comments so that they conform in style.

They all look like this now:

  /// See also:
  ///
  ///  * [MyFavoriteWidget], because it's cool.
  class Foo {}

I removed some useless "See also" blocks, and added commentary to ones that were just "bare" references.

This is my penance for adding so many bullets that are "-" instead of "*". :-)

* implicit-casts:false in flutter/lib/src/widgets

* address review comments

* address review comment

* 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 adds the ability to scroll and page up/down in a Scrollable using the keyboard. Currently, the macOS bindings use Platform.isMacOS as a check, but we'll switch that to be defaultTargetPlatform == TargetPlatform.macOS once that exists.

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

Before this change, it was possible to move the focus onto a control that was no longer in the view using focus traversal. This changes that, so that when a control is focused, it makes sure that if it is the child of a scrollable, that the scrollable attempts to keep it in view. If it is already in view, then nothing scrolls.

When asked to move in a direction, the focus traversal code tries to find a control to move to inside the scrollable first, and then looks for things outside of the scrollable only once the scrollable has reached its limit in that direction.

This adds accessors for WidgetsBinding.instance.focusManager and WidgetsBinding.instance.focusManager.primaryFocus so that they can be more easily found in IDEs and accessed.

This adds a top level getter for WidgetsBinding.instance.focusManager.primaryFocus called primaryFocus, and a static accessor FocusManager.instance that returns WidgetsBinding.instance.focusManager.

Fixes directional focus traversal when there are no available nodes to traverse to.

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 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

This adds the default shortcuts and actions for keyboard-based focus traversal of apps.

This list of shortcuts includes shortcuts for TAB, SHIFT TAB, RIGHT_ARROW, LEFT_ARROW, UP_ARROW, DOWN_ARROW, and the four DPAD keys for game controllers (because the DPAD produces arrow key events).

It doesn't yet include functionality for triggering a control (e.g. SPACE, ENTER, or controller buttons), because that involves restructuring some of the Flutter controls to trigger animations differently, and so will be done in another PR (#41220)

FocusTraversalPolicy keep the previously visited node to avoid hysteresis. But even if the visited focus has been disposed, FocusTraversalPolicy will still use it to requestFocus, which will cause FocusManger to get an abandoned node to get the focus.

Replacing the algorithm for finding the first focusable item in the focus tree. Somehow it was a kind of gibberish before, and really didn't work or make sense.

This just fixes up some comments for DefaultFocusTraversal, and fixes a minor bug when setting the onKey on a FocusNode on creation before attaching to it.

This implements focus and hover handling for Material buttons. It inserts Focus widgets into the tree in order to allow buttons to be focusable via keyboard traversal (a.k.a. TAB traversal), and Listener widgets into the InkWell to allow the detection of hover states for widgets.

Addresses #11344, #1608, and #13264.

This implements a DefaultFocusTraversal widget to describe the focus traversal policy for its children, defined by a FocusTraversalPolicy object from which custom policies may be created. Pre-defined policies include widget-order traversal, "reading order" traversal and directional traversal.