* 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

* Recreate outputFileName completer, handle process launch errors.

* Fix formatting

* Updated comment

This adds --preview-dart-2 flag that enables use of Dart 2.0 Frontend in Flutter tools.

Discovered dead code during review of #10791

* Do not lower-case paths during canonicalization.

This breaks hot reload on some platfroms with case insensitive file systems.

* Add unit tests

- [x] Catch SocketErrors and handle them gracefully.
- [x] Print 'Lost connection to device' when the service protocol connection is severed unexpectedly.
- [x] Print 'Application finished' when the application exits otherwise.

After this PR:

```
Launching lib/main.dart on Nexus 7 in debug mode...
Running 'gradle assembleDebug'...                     1.2s
Built build/app/outputs/apk/app-debug.apk (21.7MB).
Syncing files to device...
Application finished.
DevFS sync failed. Lost connection to device: SocketException: OS Error: Connection refused, errno = 111, address = 127.0.0.1, port = 53062
Could not perform initial file synchronization.
```

Fixes #6705

- [x] Skip scanning the file system if we already have the Dart dependency set.

Fixes #9376

```
Performing hot reload...
Reloaded 1 of 418 libraries in 888ms.

Performing hot reload...
Reloaded 1 of 418 libraries in 871ms.

** UNTAR dragontail under project root **
Performing hot reload...
Reloaded 0 of 418 libraries in 443ms.

** UNTAR dragontail under lib/ **
Performing hot reload...
Reloaded 0 of 418 libraries in 385ms.
```

Related #8876

* Print error message if a package is skipped during DevFS sync.

* review comments

* more review comments

* fix test