- [x] Make iOS and Android application startup paths consisitent.
- [x] Remove the now unncessary Android specific special cases from the runners.

* Allow for application-specific log readers.

When running with prebuilt application binaries, those applications
aren't guaranteed to be named "Runner" (as it is when we build
the app locally in Flutter tools)

* convert pubGet to throw ToolExit on non-zero exit code
* convert commandValidator to throw ToolExit for non-zero exit code
* convert flutter commands to throw ToolExit for non-zero exit code
* use convenience method throwToolExit
* only show "if this problem persists" for unusual exceptions

- [x] Return the reload message even when paused at a breakpoint.
- [x] Only initialize context members if they aren't already initialized.

- [x] Stop tracking time to first frame because it is unreliable.
- [x] Track time to complete reassemble instead.

* make showElapsedTime default to true

* support nested progresses

* improve hot reload message

* rethrow

- [x] Remove the second full-sync on startup.
- [x] Always invoke the snapshotter to determine the minimal set of Dart sources used.
- [x] Only synchronize the *used* Dart sources to DevFS.
- [x] Detect syntax / file missing errors on the host and gate reloads / restarts.

Fixes https://github.com/flutter/flutter/issues/6280

Fixes #4166.
Fixes #5120.
Fixes #5399.
Fixes #6507.

* add a pause parameter to the reload command

* encode OperationResult as json

* reverse isOk logic

* use less granular progress

* update restart text

This change adds a top-level getBuildDirectory func and funcs for
android, aot, asset, ios build products.

Developers may now add a "build-dir" mapping to their
~/.flutter_settings (JSON format) config file. Output directory is
relative to the main flutter application directory.

This change also changes the default build directory for iOS builds to a
subdirectory of the configured build directory, 'build/ios' by default.

This reverts commit 09e68c33.

AOT snapshotter is broken at this engine rev.

https://flutter-dashboard.appspot.com/api/get-log?ownerKey=ahNzfmZsdXR0ZXItZGFzaGJvYXJkclgLEglDaGVja2xpc3QiOGZsdXR0ZXIvZmx1dHRlci8wOWU2OGMzM2NjZGIzNTVmZWRkNzVhODcxNmRlMDU1MWM3NzJmMmRlDAsSBFRhc2sYgICAgICAwAgM

* fix an issue where --hot would not exit

* add type annotations

- [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 the base uri back to debuggers

* add a fullRestart parameter to app.restart

* add await