* Fix typos

* lowercase animated & opacity

* Undo typo fix

---------
Co-authored-by: Michael Goderbauer <goderbauer@google.com>

* Rename WindowPadding to ViewPadding

* dart fix

* typos

* [web] Temporarily disable a line boundary test

* [web] Unify line boundary expectations on web and non-web

* Add test for RenderProxyBoxMixin; clarify doc, resolve TODO

The TODO comment suggested this mixin would no longer be needed once
a Dart issue on inherited constructors was fixed:
  https://github.com/dart-lang/sdk/issues/31543
That issue is now long since fixed, so I went to go carry out the TODO.

But in doing so, I realized that the mixin's documentation was more
right than the TODO comment: even with that issue fixed, there is a
legitimate use case for this mixin, namely to reuse the implementation
of RenderProxyBox in a class that also inherits from some other base
class.  Moreover, searching GitHub I found an example of a library
that makes real use of that capability.

So I think the right resolution is to accept that this separation
is useful and delete the TODO.

Then, add a test with an extremely simplified sketch of that
real-world example.  In case someone in the future attempts to
simplify this mixin away, the test will point us at the use case
that would be broken by such a change.

Also remove the only in-tree use of the mixin, which was redundant;
and expand the mixin's documentation to advise about that case.

* Tweak formatting
Co-authored-by: Michael Goderbauer <goderbauer@google.com>

* Cut comments

---------
Co-authored-by: Michael Goderbauer <goderbauer@google.com>

* [framework] use shader tiling instead of repeated calls to drawImage

* ++

* ++

* review and test updates

* ++

* Update decoration_image.dart

* Update decoration_image.dart

* ++

* ++

* ++

* ++

* ++

* Update painting.dart

* Update decoration_test.dart

* Make Flex,Row,Column const for real

* dart fix --apply

* fix snippets

* fix integration test

* add comment

* PostFrameCallbacks -> compositionCallbacks

* review

* review

* Avoid affinity like the plague

* ignore lint

* clean up

* fix test

* review

* Move wordboundary to text painter

* docs

* fix tests

* Enable  lint

* note about discarded_futures

* note about use_decorated_box

* update note on require_trailing_commas

* Floating cursor cleanup

* Use TextSelection.fromPosition

* Add selection feedback for both selection area and text field

* Addressing comment

* Fixes more test

* Use upper AnnotatedRegion properties when no bottom one found (and vice versa)

* Update comments
Co-authored-by: Bruno Leroux <bruno.leroux@gmail.com>

* Support keyboard selection in selectable region

* fix some comments

* addressing comments

Fix that RenderEditable (TextField) ignores offset in painting, making text selections shifted when offset is nonzero (#109287)

Small fix in text layout math, unlikely to affect most normal usages.