- remove an //ignore that is no longer needed
- fix some intrinsic methods that used the API incorrectly (shouldn't affect correctness but should make things a tiny bit more efficient)
- add some asserts to help track down bugs quicker
- update a TODO to point to the currently relevant bug
- fix some indenting
- improve the naming of some privates to improve readability

Fixes the pattern for some TODOs to match our style guide.

(Also, a couple of minor code order fixes.)

* `flutter analyze` cleanup

* Make `--dartdocs` work in all modes.
* Make `analyze-sample-code.dart` more resilient.
* Add a test for `analyze-sample-code.dart`.
* Minor cleanup in related code and files.

* Apply review comments

* Fix tests

* Fixes resulting from audit of issues links

I looked at every link to GitHub in our repo. For cases where we had a TODO that was waiting for a bug to be fixed, and the bug has now been fixed, I applied the pending change. For cases where the link was out of date, I updated the link.

* Update run_test.dart

skip this test again since it failed on linux and macos bots

With this change you can now create "wrapping" text fields that do not show the new line button:

```dart
new TextField(
  maxLines: null,
  keyboardType: TextInputType.text,
);
```

Allows the cupertino picker to be scroll infinitely by adding builder.

This adds the animation links for illustrations of the Transition widgets, as well as adding a cross-references to the other transition widgets in the "See also" for each of their docs.

Adding CupertinoActionSheet, showCupertinoModalPopup

* Visibility widget

This attempts to address the confusion around how to hide a widget subtree.

* Apply review comments

* More clarifications

This fixes https://github.com/flutter/flutter/issues/18057

Add minOverscrollLength to make CupertinoScrollbar thumb correct size in long scroll views.

This PR adds 2 features to RenderAndroidView and AndroidView:

1. Hit testing behavior
Adds a `PlatformViewHitTestBehavior` which is similar to
`HitTestBehavior` without the `deferToChild` option (as platform views
don't have child render objects) and with a `transparent` option which
prevents it from forwarding any events to the Android view.

2. MotionEvent recomposing logic
FlutterView and the framework `converter.dart` are working together to
transform each Android MotionEvent object into one or more
`PointerEvent` objects.

This PR adds the reverse logic (in _MotionEventDispatcher which is used
by RenderAndroidView) which turns a stream of PointerEvent objects into
MotionEvent objects.

The correctness of the recomposing logic is tested in an integration
test which will land in a separate PR (the unit test PR is pretty big,
trying to keep as many bite-size PRs for reviewer's convenience)

* no blinking cursor

* debugDeterministicCursor: private -> public

* added documentation

* whitespace

See details in our proposal for this breaking API change and #18057. This PR setup all code paths to allow the change but doesn't change the clip behavior by itself. We'll change `defaultClipBehavior` from `Clip.antiAlias` to `Clip.none` in the following PR to change the clip behavior and update tests.

Fixes #19617

Fixes #19523

It was causing problems rolling Flutter into Fuchsia

Updated documentation of SizeTransition, since I found it less than intuitive.

I added some constructor asserts to make the (existing) contract more clear.

Changes:

- Move the SemanticsConfiguration update from RenderToggleable to each subclass, so that Switch can use toggled.
- Add image, liveRegion, toggled properties to Semantics, SemanticsConfiguration, SemanticsNode
- Added semanticsLabel and excludeFromSemantics to Image (the latter so that we avoid creating a semantics node)
- Added onDismiss semantics action which maps to the modal escape on iOS and dismiss action on Android.
- Added dismiss and liveRegion to snackbar widget
- Updated custom painter semantics to handle image, liveRegion, toggle
- Updated relevant tests to use correct flag/action