In the legacy VS Code DAP, we would deserialise the Flutter.Error event
and provide some basic colouring (eg. stack frames are faded if not from
user code and the text is split between stdout/stderr to allow the
client to colour it).
In the new DAPs we originally used `renderedErrorText` which didn't
support either of these. This change adds changes to use the structured
data (with some basic parsing because the source classes are in
package:flutter and not accessible here) to provide a similar
experience.
It would be nicer if we could use the real underlying Flutter classes
for this deserialisation, but extracting them from `package:flutter` and
removing all dependencies on Flutter is a much larger job and I don't
think should hold up providing improved error formatting for the new
DAPs.
Some comparisons:


When building the new SDK DAPs, this functionality was missed from the Flutter adapter (but added to the Dart CLI adapter).
As well as passing a VM Service URI directly, we support passing a file that can be polled for it.
This uses the same mechanism we use to obtain the VM Service URI from a Dart debug session (we run `dart --write-service-info=foo.json my_file.dart` and then poll that file which the VM will write) and is useful for users that have their own mechanism for launching an app (for example using custom Flutter embedders - see https://github.com/Dart-Code/Dart-Code/issues/3353) to provide a VM Service URI once the app is up and running.
Fixes https://github.com/Dart-Code/Dart-Code/issues/4577.
The editor is set to hot-reload-on-save by default so saving while the debug session is starting currently prints an error:
Failed to Hot Reload: app 'null' not found

This change skips the call to `app.restart` if the app hasn't started yet to avoid printing an error.
* [flutter_tools] Forward app.webLaunchUrl event from Flutter to DAP clients
Fixes https://github.com/Dart-Code/Dart-Code/issues/4292.
* Update packages/flutter_tools/lib/src/debug_adapters/flutter_adapter.dart
Co-authored-by: Christopher Fujino <fujino@google.com>
* Another static const instead of final
Co-authored-by: Christopher Fujino <fujino@google.com>
* [flutter_tools/dap] Add support for forwarding `flutter run --machine` requests to the DAP client
Currently the only request that Flutter sends to the client is `app.exposeUrl` though most of this code is generic to support other requests that may be added in future.
* Improve comment
* Fix thrown strings
* StateError -> DebugAdapterException
* Add a non-null assertion and assert
* Use DebugAdapterException to handle restartRequests sent before process starts
* Fix typo + use local var
* Don't try to actually send Flutter messages in tests because there's no process
* [flutter_tools] [dap] Ensure DAP sends app.stop/app.detach during terminate
Fixes an issue where the flutter_tester device may not be cleaned up correctly if we just terminate the Flutter process.
* Update integration test expectations
* Revert accidental commit
Since 02d9c3e6a5 this flag does absolutely nothing. The behaviour it controlled is now automatic and the flag is not required.
The flag will be removed from the Dart SDK in the future after Flutter is no longer using it.
* [flutter_tools] [dap] Add support for passing env variables to spawned processes
* Use named args
* Use in-memory fs and FakePlatform
* Pass filesystem style to MemoryFileSystem
* Fix issues running integration tests through DAP
These adapters were incorrectly trying to connect a DDS instance even when Flutter would create its own. This change disables DDS in the DAP layer and leaves it to Flutter (although it passes `--no-dds` on to Flutter if provided to the DAP process).
Also fixes an issue where we would unnecessarily connect the VM Service for tests even in 'noDebug' mode because of a change/fix that now includes a 'vmServiceUri' in the `test.startedProcess` event.
* Don't terminate Dart process pids from VM Service
These processes may be on another device, and in the case of attach the debugee should not be terminated anyway.
* Add support for attachRequest in DAP, which runs "flutter attach"
* Update DAP docs for attachRequest
* Improve doc comments
* Fix comments
* Remove noDebug from attach + create a getter for `debug`
* Fix indent