- [x] Refactor view support into separate classes.
- [x] Make the hot runner grab the main view and call runFromSource on it.
- [x] Remove Device.needsDevFS (because it is always true).

* send ext.flutter.debugDumpApp; ext.flutter.reassemble

* expose debugDumpRenderTree

Enable launching applications on the iOS device with observatory and diagnostics server connected. (#4424)

* send supportsRestart flag when starting an app

* remove unused imports

* review comments

* refactor the --resident run option into a separate file

* update daemon to run --resident apps

* re-plumbing daemon start

* send app logs

* update tests

* review changes

* fix test runner

* remove PackageMap.createGlobalInstance; rely on the ctor

* review comments

* working on making a faster flutter run restart

* clean up todos; fire events on isolate changes

* use the Flutter.FrameworkInitialization event

* review comments

For consistency.

Fixes #4142

Wire up ios-profile and ios-release. Switching between debug, profile and release starts the build process from scratch. (#4063)

Quick pass at fixing a few dangling references as revealed by the new `comment_references` lint (https://github.com/dart-lang/linter/issues/240).

There's a bunch more to do here before we can turn it on by default (~430 lints as of now).  Many of them are a simple matter of adding an import (e.g., `dart:async` for library docs that reference `Future`) but others will require a bit of thought.  Probably best done by the folks writing the code. :)

This also fixes some related problems affecting "flutter run":
  * FLXes built during AndroidDevice.startApp need to match the build mode
  * APKs should always be rebuilt if the build mode uses AOT compilation

* rename service_protocol.dart to protocol_discovery.dart

* add a wrapper around the obs. protocol

* use json-rpc in run

* consolidate obs. code; implement flutter run --benchmark

* review comments

Artifacts from local engine builds will be found based on the --local-engine flag

Host tools can be found in the artifact cache directory for the host platform.
If a developer wants to use a local engine build instead, then provide an
--engine-build flag that selects the specific engine build variant.

* send ext.flutter.exit

* listen for help restart, quit

* refactor into a separate class

* fix analysis errors

* review comments; fix test

* re-add an export for debugPrint

* rework flutter run

* fix npe with --debug-port

* connect to obs and exit when that conneciton closes

* update todos

* use the new cache code to locate more artifacts

* add todo

* review comments

* better messaging about windows support

* fix lints

Add a command that can capture a Skia picture of a Flutter frame and send it to a file or skiaserve debugger (#3165)

Well, all the easy ones, anyway.

For some reason `// ignore:` isn't working for me so I've disabled
lints that need that. Also disabled those that require a ton of work
(which I'm doing, but not in this PR, to keep it reviewable).

This adds:
- avoid_init_to_null
- library_names
- package_api_docs
- package_names
- package_prefixed_library_names
- prefer_is_not_empty
- sort_constructors_first
- sort_unnamed_constructors_first
- unnecessary_getters_setters

flutter start's method of finding devices to run the app on is not suitable for flutter drive.

This commit also refactors several tool services to allow mocking in unit tests.