This reverts commit 1705bf3c.

* Revert "Fix a typo in the saved certificate error message (#11640)"

This reverts commit bfda885a.

* Revert "Rollback patch that broke microbenchmarks (#11616)"

This reverts commit 70fe6f4c.

* Revert "Extract snapshotting logic to Snapshotter class (#11591)"

This reverts commit 309a2d78.

* Revert "Minor whitespace formatting fix (#11590)"

This reverts commit bf69c3c6.

* Revert "Avoid rebuilding snapshots if no change to source (#11551)"

This reverts commit 74835db5.

* Let android create template have an explicit flutter splash screen flag

* minor language tweak

* Revert "Create template splash screens for Android and iOS (#11505)"

This reverts commit 1ad4a088.

* Revert "Roll engine (#11619)"

This reverts commit ea78f448.

* Add iOS template

* Android

* Let the engine reset the theme without the activity knowing

* Small tweak

* Replace assets with different vectors

* Let the template hookup have no actual image assets

* Add back placeholder assets with 1px transparent pngs

* Fix drawable xml

* clean up an extraneous line in the storyboard xml

* roll

* kick the tests again

* Revert "kick the tests again"

This reverts commit 4480a02ce2d60e66ad0ca8ac5a2029f84f9b71d9.

* Let the initial date picker mode be selectable

* Doc for enum

* Add a test

* Add a comment for test

* actually decouple test from setup state

* Wrap the label widget of the Chip in a Flexible. (#11523)

* This allows the Chip to constrain the size of its content after taking into account the space occupied by the avatar and delete icon (if they are present)

* Adding unit tests to evaluate correct size constraints of the Chip widget's label. (#11523)

* Minor change in formatting.

* Adjust function formatting.

First step in eliminating code duplication between script snapshotting
(in FLX build) and AOT, assembly AOT snapshotting.

Adds some missing spaces.

* Add synthesized property to pointer events

* test

* Make iOS back gesture triggerable from the edge only.

* change to positioned

Fixes https://github.com/flutter/flutter/issues/11539

* Bump Dart SDK to 1.25.0-dev.9.0

* add link to sdk bug

* Make tear-offs cachable for RenderSemanticsGestureHandler

Fixes https://github.com/flutter/flutter/issues/11552

* comment fix

* refactor

* a11y: handle left/right scrolls correctly

* fix keep alive test

* fix scaffold test

Don't trigger an assert when markNeedsSemanticsUpdate is called multiple times in edge cases (#11544)

* Don't trigger assert if a render object ceases to be a semantic boundary

This bug was exposed by https://github.com/flutter/flutter/pull/11309, which caused the following assertion to trigger when scrolling in the Animation demo:

```
The following assertion was thrown during _updateSemantics():
'package:flutter/src/rendering/object.dart': Failed assertion: line 2626 pos 16: 'fragment is
_InterestingSemanticsFragment': is not true.
```

A minimal reproduction of the bug can be found in `semantics_10_test.dart`, which has been added as a regression test for the bug by this PR.

Looking at that test, here is a description of the faulty behaviour:
1. During the second `pumpWidget` call `RenderExcludeSemantics` marks itself as needing a semantics update (due to excluding going from `false` -> `true`).
2. This causes the nearest ancestor with semantics information (here: `RenderSemanticsAnnotations` representing the "container" Semantics widget) to be added to the `_nodesNeedingSemantics` list.
3. `RenderSliverList` (implementation behind ListView) marks itself as needing a semantics update (due to its changing children).
4. This causes the `RenderSemanticsGestureHandler` to be added to the `_nodesNeedingSemantics` list.
5. Next, canDrag is updated from `true` -> `false`. This means, `RenderSemanticsGestureHandler` is no longer a semantics boundary, it marks itself as needing a semantics update.
6. The nearest ancestor with semantics (`RenderSemanticsAnnotations`, the "container") is added to the `_nodesNeedingSemantics` list (this is a no-op because it is already in the list).
7. During `flushSemantics`, the `_nodesNeedingSemantics` list is walked. The first entry (`RenderSemanticsAnnotations`) updates the semantics tree to only contain the container widget and drop everything else (= no children of the ExcludeSemantics widget are walked).
8. The second entry (`RenderSemanticsGestureHandler`) is updated. It does not add any semantics of its own and is no longer a semantics boundary. Therefore, it wants to merge its descendent semantics into its parents. Here is where the assert throws because the algorithm assumes that every entry in the `_nodesNeedingSemantics` list will produce and own an `_InterestingSemanticsFragment` (passing your semantics on to your parents is not interesting).

The problem here seems to be step 4 in combination with step 5. In step 4 we rely on the fact that `RenderSemanticsGestureHandler` is an (explicit or implicit) semantics boundary and that it will be able to absorb the semantics change of `RenderSliverList`. This is true
at this time. However, in step 4 `RenderSemanticsGestureHandler` decides to no longer be an (explicit or implicit) semantics boundary and our assumption from step 5 becomes incorrect. We did nothing to correct this assumption.

This PR removes a node, that could potentially cease to be a (explicit or implicit) semantics boundary from the `_nodesNeedingSemantics` list to fix that problem. Please node that this does not mean that the node's semantics will not be updated: The node's closest ances
tor with semantics is added to that list during the `markNeedsSemanticsUpdate` call. During `flushSemantics` we will walk from this node to update the semantics of it's children (if changed), which will include the node in question.

* tiny fix

* simplify test

* analyzer fixes

* review comments

This change re-introduces skipping snapshot builds if input sources (and
outputs) have not changed since the last snapshot build, with a bugfix
to include the entry-point source in the checksum used to check whether
rebuild can be skipped. This ensures that the following sequence
invalidates the cached build, resulting in two snapshot builds:

  flutter build ios lib/foo.dart
  flutter build ios lib/bar.dart

This reverts commit 3d5afb5a.

* Allow tapping on TabBar indicator to switch tabs

* fix semantics

* review comments

Roll engine in order to fix regression of AOT snapshot build time.

I forgot to do this when I updated our test package.

The most recent Flutter IntelliJ plugin replaces FLUTTER_MODULE with
WEB_MODULE and eliminates the exclusion of packages/ directories.
Use of the packages/ directory was turned off by default months ago, and
is replaced by the .packages file.