* Remove uses of deprecated constants
* Change int.parse to int.tryParse where appropriate

* Preserve original kernel file for isolate spawn requests.

This change gives incremental kernel files ".incremental.dill" extension thereby preserving original kernel file.

Bug: https://github.com/flutter/flutter/issues/16084
Bug: https://github.com/flutter/flutter/issues/17012
Bug: https://github.com/flutter/flutter/issues/17983

* Factor out naming logic into separate function

* Fix string vs uri

fuchsia_tester.dart still assumes Dart 1. Previously, it ran tests directly
from source, flutter_platform.dart automatically runs a kernel compile when
operating in Dart 2 mode, but this assumes a functional Dart SDK is available
in the artifacts directly, and fuchsia_tester.dart mocks out the artifacts
directory with an empty temp dir.

Remaining work is:
1. Get the frontend server building as a dependency on Fuchsia.
2. Patch fuchsia_tester.dart to use a valid Dart SDK and frontend server.

This also reverts migration to Dart 2 typedef syntax.

This reverts commit 6c56bb24. (#18362)
This reverts commit 3daebd05. (#18316)

* It's time to #deleteDart1 (#18293)

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

* Fix indentation, remove no longer necessary .toList()

* Only push udpated kernel if >0 invalidated srcs

Several benchmarks started failing during kernel compile:
1. Timeouts:
   * commands_test
   * hot_mode_dev_cycle__benchmark
   * run_machine_concurrent_hot_reload
   * service_extensions_test

2. Kernel compiler crash:
   * hot_mode_dev_cycle_linux__benchmark
   * routing_test

3. Unexpected termination:
   * hot_mode_dev_cycle_win__benchmark

This reverts commit ed63e708.

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

DevFS.update() returns the number of bytes synced from the host to the
target device. When running in Dart 2 mode, ensure that the size of the
kernel file is included in the count of bytes synced.

Iterates over a copy of the dirty entries list rather than the original,
in order to avoid the potential for a concurrent modification exception
when fileUris are removed/added later in the loop.

This occurs when non-asset URIs (Dart sources) are listed in the dirty
set when --preview-dart-2 is enabled (the default).

The new values are not ready for use yet inside Google

* Roll engine to e976be13c51448f89107d082ec81e2b6731671fa

* move away from deprecated constants

* Handle error count reported by frontend.

Extend compilation result from single string to a structure(string filename and integer error count).

* Use ?.

* Include engine roll with dart sdk roll.

* parse(onError) -> tryParse

* Make '?? throw' more readable and avoid issue with analyzer

* Fix test so it mocks compiler output including errors count

* Sync .packages file as regular file.

Currently .packages file is treated specially as DevFSStringContent to accommodate package-file rewrite when it is sent to the device for dart1 compilation. In dart2 we need to treat .packages as regular file because from frontend perspective it's just a normal input file.

* Use uris for hot reload invalidation.

* Clean up unneccessary conversions

* add final.

* Revert sample change

* Revert "Revert "Reland pass filesystem options (#15622)" (#15651)"

This reverts commit 0f3eada0.

* Fix for windows failing test

* !isEmpty -> isNotEmpty

This reverts commit bbcf55a5 as it breaks hot reload on Windows.

* Revert "Revert "Pass filesystem-root, filesystem-scheme options through `flutter run, build` and gradle. (#15592)" (#15621)"

This reverts commit c663e336.

* Check whether filesystem-root is emtpy.

* Restore broken merge

* Fix windows test

* Adjust regex in test. Invalidate files by file path.

* Add to Artifacts, and add optional arguments to entry points for flut… (#15185)

Add to Artifacts, and add optional arguments to entry points for flutter run and test to allow for wiring up the same with preview-dart-2 internally

* Changing packages uri here is not necessary

This reverts commit e0f6e626.

Add to Artifacts, and add optional arguments to entry points for flutter run and test to allow for wiring up the same with preview-dart-2 internally

* Put generated kernel files into <build> directory

* USe default value for kernel file

* [kernel/flutter] Improve speed of first hot reload

* [kernel/flutter] Improve speed of first hot reload

* Revert "[kernel/flutter] Improve speed of first hot reload"

This reverts commit f3dc133878ec7405a8efb5715f1cfe720f4ea05f.

* Revert "[kernel/flutter] Improve speed of first hot reload"

This reverts commit f7bcb082b01cf9cf48f02c6aad9e5c79705def8f.

* Revert "Revert "[kernel/flutter] Improve speed of first hot reload""

This reverts commit 73c7a1a8e85a4c0397984d8b65a98b2f71bf84f3.

* [kernel/flutter] Improve speed of first hot reload

Do so by not evicting unnecessary paths (while still evicting paths
that was changed between the generation of the package file and the
initial upload).

* Fix grammar in method name

* Fix bad merge

* Add method to super class

* Use IKG for restarts, use IKG with ProtectedFileByteStore.

* Fix comment, add end of file newline.

* Remove unused import

* enable lint prefer_foreach

* fix tests

Syncing source files is not needed when host sends kernel file to the device.

* Keep incremental compiler state through full restart.

* Add todo

* Add todo

Reapply "When parts of the program are changed in a hot reload, but not executed during the reassemble, warn that a restart may be needed." (#12490)

This reverts commit 5e7bcbac.

`flutter run --benchmark` was triggering a different quick bailout path in the VM than `flutter run`. The failure has been fixed upstream.

* Fix restart flow for preview-dart-2 mode.

Restart in preview-dart-2 needs to use kernel file and it has to be complete, rather than incremental kernel file.

* Add curly braces

* Do full compile on restart

* Roll engine to pick up changes to hot reload for preview-dart-2

Revert "When parts of the program are changed in a hot reload, but not executed during the reassemble, warn that a restart may be needed. (#12304)" (#12406)

This reverts commit 90028813.

This change caused a few bots to fail with 'JSON-RPC error 110: Extension error', which is odd because _getUnusedChangesInLastReload is not an extension.

When parts of the program are changed in a hot reload, but not executed during the reassemble, warn that a restart may be needed. (#12304)

* round 3

* partially address comments

* merge

* review notes

* review

* review

* review