Introduced by merging an old PR (https://github.com/flutter/flutter/pull/21157).

Fixes #20893, the most-upvoted bug for framework.

A detailed analysis explaining the cause of the bug has been posted at #20893 (comment).

* Register hot restart service in flutter_tools.

This will help track down any that aren't cleaning up and also may help track down leaked flutter_tester processes (https://github.com/dart-lang/sdk/issues/35549).

https://github.com/flutter/engine/compare/3c0aa918de87...25559ed07796

git log 3c0aa918de8782ed73b12fc148c4ab7cb6ed1416..25559ed0779604d56c47c5d2341ffd16b137cd10 --no-merges --oneline
25559ed07 Wrap the user entrypoint function in a zone with native exception callback. (flutter/engine#7512)
1b0d09b21 Roll src/third_party/dart f701e11756..700254996f (5 commits) 700254996f [ Observatory / Dartium ] Updated observatory documentation and tests to remove references to Dartium. 78abb98ee7 [vm/bytecode] Fix AST removal for package-split kernel files with bytecode 0075b58bb8 CHANGELOG entry for DEPRECATED_MEMBER_USE split a5f102a7d1 Analyzer: first pass at reporting unchecked nullable value usage. a10ddca1b1 [ VM / Service ] Allow for `profile_period` flag to be set via the service protocol
e7ade51da Remove unused headers (flutter/engine#7511)
369b4db35 Roll src/third_party/skia 1374c85fbf53..081e6f375497 (6 commits) (flutter/engine#7510)
366d44e11 Roll src/third_party/dart 9b5eabdaca..f701e11756 (10 commits) f701e11756 [ VM / Debugger ] Fix issue where a 'Step' command issued when there's no stack caused a crash. c5bfccc6fb Make downloading the LSP spec a flag and commit the version parsed locally dbeec3bbf3 Fix formatting in generated LSP file header bfe15d87d8 Fix LSP exceptions serializing ResponseErrors with Uris 7984dc4fcc Prepare to publish analyzer version 0.34.2. 4b1b2f9176 Switch LSP formatter to not fetch resolved ASTs that aren't used 5ce5d697da Implement LSP code folding b47524d5b0 Ensure all unhandled exceptions are recorded on the server 8ba2de2344 Sort context for conflicting inherited members 215f6620e7 [Kernel] Signal errors on static fields in constant contexts
1e93a8eb3 Deprecate FlutterProjectArgs.main_path, packages_path (flutter/engine#7497)
b058920ca Edit the bundleid so that it conform to UIT specifications. (flutter/engine#7503)
32c9ae616 Roll src/third_party/skia 2c379d8e27e6..1374c85fbf53 (4 commits) (flutter/engine#7508)
96d10b184 Roll src/third_party/dart 492df72739..9b5eabdaca (8 commits) 9b5eabdaca Fix crash in color support a533753bec Remove --fast-startup flag support from testing scripts and status files 5f10aed19c [Kernel] Don't print static fields in instance constants bdb51e2837 Improve input path handling and remove extra schemas. 0604110806 Reduce expectations on thrown exception 966e007b63 Pass CallStructure on dynamic and static use in ResolutionWorldBuilder 3e7801294e Remove unneeded code in OrderedTypeSet 8a91948c03 [Kernel] Properly signal compilation errors for constants
770984088 Roll src/third_party/skia a8694cc150a1..2c379d8e27e6 (1 commits) (flutter/engine#7506)
046ddc68d Roll src/third_party/skia 47b7cd9a6baf..a8694cc150a1 (1 commits) (flutter/engine#7504)

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the roller if necessary.

* Fixes Android keyboard bug

This reverts commit d8db70af.

* move flutter_assets to App.framework

* remove flutter_assets references from all pbxproj files checked in

Newer NDKs switched to clang which by default uses system linker, instead
we need to force it to use appropriate toolchain linker by passing
-fuse-ld= command line flag.

Fixes #23458

This reverts commit 9880baa3.

Reason for revert: broke `--local-engine` command line option.

Generally, we should always use default-less switches for
platform-specific behaviour so we're forced to make a conscious decision
on each instance of such behaviour any time we add support for a new
platform.

* Add labelStyle + unselectedLabelStyle to TabBarTheme

The lerp method for IconThemeData was not doing anything to prevent exceptions when null arguments are used. This change fixes that and adds a test for it.

3c0aa918d Roll src/third_party/dart 2195a70249..492df72739 (2 commits) 492df72739 Fix fasta test under windows 4ec9dbf1d0 Add set literal spread collection parsing support (#26645)


https://github.com/flutter/engine/compare/09e149e89787...3c0aa918de87

git log 09e149e89787fb0722b8a43ec5406e66d6901eec..3c0aa918de8782ed73b12fc148c4ab7cb6ed1416 --no-merges --oneline
3c0aa918d Roll src/third_party/dart 2195a70249..492df72739 (2 commits) 492df72739 Fix fasta test under windows 4ec9dbf1d0 Add set literal spread collection parsing support

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
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* Include caret gaps in position calculation to avoid descender cutoff

* Calculate caret offset instead of exposing it

* Test that textfields scroll vertically by full line height

* Only add offset to end of caret to avoid going above 0.0

* Fix and test horizontal vs. vertical scrolling

* CR: docs and top caret offset logic

* Take max instead of assuming caretRect.top is always a full line down

* Always subtract caretOffset from caretTop since caretRect.top can be negative

https://github.com/flutter/engine/compare/fdfb0e72f0af...09e149e89787

git log fdfb0e72f0af7b4de3f8cd04ca8519ba5acc12fe..09e149e89787fb0722b8a43ec5406e66d6901eec --no-merges --oneline
09e149e89 Roll src/third_party/skia 98c65fc9558f..47b7cd9a6baf (4 commits) (flutter/engine#7501)
87e8d3059 Roll src/third_party/dart d9944433af..2195a70249 (28 commits) 2195a70249 Make sure that path is correct on all test platforms 56f87f409e [dart:io,fuchsia] Pass Isolate namespace to child process. Fix double free. b55bc09f1f Add list literal spread collection parsing support 4074ebd0a0 Partial implementation of the unified specification of definite assignment, type promotion, and reachability analysis. 43a96d49af Revert "[vm/compiler] AOT inline heuristics improvements" a55b6fc183 Remove unused import 2908e61f2a [vm/compiler] AOT inline heuristics improvements 3154bb0d37 Stop using external deprecated members in front_end ff06d233aa Set CompletionSuggestion.elementUri everywhere in analysis server that element is already being set. 23f427b1a7 Reland [VM/Compiler] Removing definition status from Store{Indexed,InstanceField}. edca6169c1 Fixed a number of dart:html P1 issues. ff5e5b6896 Regenerate LSP classes from spec + update README 116f678a69 [build] Enable mitigations for Cortex-A53 Erratum #843419 bug. 21edbbbac6 Add spread collection token to scanner 030fa85cea Fix windows tests 23b5aee978 Update dartfix NNBD to handle more situations fe6b384ff5 revise dartfix protocol version check 61e81217f0 Update LSP status doc (rename is complete + tested in VS Code) daead8dff8 Add test for LSP rename that edits multiple files bdade89081 Improve testing of document versions in LSP renames ecc1411685 Print constant table when printing libraries. 999c2a7582 Check for conflict with static members 3f44bd1bf9 Check for conflicts in mixins aa59b20b4b Don't report conflicts twice 3ef8c296bd Improve detection of conflicts with inherited members and setters 50fa633c4a Report InheritedMembersConflict correctly c25c30dc32 Remove some unused imports c6ab52c9f9 Using the right conjunction
6c68bf3ca Revert "Revert "Add elevation and thickness to SemanticsNode (#7282)" (#7483)" (flutter/engine#7484)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

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https://github.com/flutter/engine/compare/5983e34a3c0e...fdfb0e72f0af

git log 5983e34a3c0e1217da7e8bbe9f2fe685048fe259..fdfb0e72f0af7b4de3f8cd04ca8519ba5acc12fe --no-merges --oneline
fdfb0e72f Roll src/third_party/skia cb7149e05864..98c65fc9558f (3 commits) (flutter/engine#7498)
5401803f6 Validate dynamic patches before attempting to install (flutter/engine#7496)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

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Generally, we should always use default-less switches for
platform-specific behaviour so we're forced to make a conscious decision
on each instance of such behaviour any time we add support for a new
platform.

I fixed this TODO a while ago during my a11y work.

Previously, a disabled floating action button always had zero
elevation, which looks dumb.

This also fixes the issue whereby highlightElevation was not honoured
on floating action buttons.

This also fixes an issue I found during testing whereby setState was
being called during build when onHighlightChanged fired due to
onPressed becoming null while a gesture is ongoing (which triggers an
onTapCancel synchronously during build).

Adds asserts on required constructor parameters to a transition widgets.
This improves debuggability for those who aren't developing with live
analysis. e.g. when `turns` is not specified in a RotationTransition
constructor:

  package:flutter/src/widgets/transitions.dart: Failed assertion: line 43 pos 15: 'listenable != null': is not true.

becomes:

  package:flutter/src/widgets/transitions.dart': Failed assertion: line 259 pos 15: 'turns != null': is not true.

copySharedFlutterAssetsTask copies the `flutter_shared` folder assets to android's `src/main` folder of Flutter project, so that folder is bundled on the generated AAR

This was added to make sure we don't crash before the engine is rolled
with the system channel API addition and is no longer needed.