Made flutter tools serve metadata produced by the frontend server:

pass --experimental-emit-metadata flag to flutter engine
store and serve metadata from web asset server
store and serve merged metadata from web asset server
add tests to verify that metadata is served from memory
update dwds version so it can read metadata
configure dwds to read metadata from file
Prerequisite changes (landed):

sdk: https://dart-review.googlesource.com/c/sdk/+/150181
flutter engine: flutter/engine#19168
webdev:dart-lang/webdev#1064

In web debug mode, infer sound null safety by default. When sound null safety is enabled, provide a separate dill and precompiled Dart SDK. Release builds do not need this setting since we run dart2js from source.

Fixes #59873

Last batch of test fixes for general shard.

The global packages path could cause tests to fail when it would be overriden to unexpected (in test setup) values. Remove most usage and make it a configuration on buildInfo, along with most other build information. Cleanup the asset builder to require the .packages path and the resident runners to no longer require it, since they already have the information in build_info.

It needs to stick around for the fuchsia deps we do not control.

Filled #60232 for remaining work.

WebAssetServer could fail if some of the global statics it depended on were initialized in a different order. Fix this by removing globals.

Delete dwds startup test that needs to spawn a real server.

Fix tests broken under tester

Fixes additional bugs uncovered by tester, style fixes to prevent suggested imports.

Update all versions, specifically file which fixes some bugs that caused tests to fail if run in different orders:

- systemTemp directories created by MemoryFileSystem will allot names based on the file system instance instead of globally.
- MemoryFile.readAsLines()/readAsLinesSync() no longer treat a final newline in the file as the start of a new, empty line.
- RecordingFile.readAsLine()/readAsLinesSync() now always record a final newline.

Support Microsoft Edge as a device for flutter run when web is enabled. Currently this only works on Windows, and does not include a validator for edge.

Fixes #55322

instead of restricting profile/release mode based on whether the tool thinks the device is an emulator, restrict based on the device target architecture and the requested build mode. Notably, this enables release mode on x86_64 Android emulators, but not x86 emulators since we do not support that as an AOT target.

This does not add release mode support for simulators, since this requires us to build and upload artifacts for simulator/x86_64

Make it possible for all FlutterCommands to be global free, by moving instantiation to inside the Zone context. Additionally, provide VerboseLogger and NotifyLogger (daemon) at the top level and remove from command-specific overrides.

This allows removing a work around where web devices needed to look up directly from the context in non-test code.

Technically the output preferences are still zone injected, but these will be moved soon as they were not being used correctly by the top level command (the injection comes after ArgParser reads the overflow values, causing numerous wrap issues)

Fixes #56194

Remove caching of FlutterView and poll forever if the list of flutter views is empty. Added test for missing release mode logic.

This reverts commit 209bdcb6.

Remove caching of FlutterView. Perhaps the FlutterView RPC might return an empty list if the VM is not quite up yet? We had some old logic to poll the flutter views RPC for up to 200ms. That doesn't seem like a great approach, so instead we could forgo it entirely and trust that either the views come up before the developer tries to interact, or we crash.

Constructing the WebDevices with the global logger too early will lead to them grabbing the StdoutLogger when running in daemon mode. This prevents IDEs from seeing the correct debug message.

[flutter_tools] set test directory base as additional root, allow running without index.html (#55531)

save and restore the chrome session local storage information

Should fix issues introduced in web-server device and allow loading org-dartlang-app URIs

* Fix web test flakiness; enable web golden tests

The fix is three-part:

- Only allow one test to load _and_ test at any point in time.
- Use a fresh Chrome instance for each test file.
- Increase Cirrus resources.

The first two changes only fix the "Unknown error loading" error, but not hanging tests. The resource increase also prevents hanging tests.

Other minor changes:

- Remove test batching (it's no longer necessary)
- Fix the Chrome class, which was using the wrong Completer.

Update to latest dwds APIs, moving back to dwds driven hot restart and enabling future work on expression evaluation.

This is required to roll forward package:vm_service to 3.0.0 and is
blocking a DevTools release.