This reverts commit 8b6baae4.

This is in preparation to move the flutter artifacts to a more secure
location.

Bug:
  go/fxb/64576

Our current top crasher is an unclear error when ProcessManager fails to resolve an executable path. To fix this, we'd like to being adjusting the process resolution logic and adding more instrumentation to track failures. In order to begin the process, the ProcessManager has been folded back into the flutter tool

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

Fixes #74772

stale files from previous SDKs were getting left in the cache, confusing the analyzer.

initialize the flutter root as early as possible. This allows all interfaces to be normally injected into commands, even if those objects might read from the flutter root.

Moves the flutter root initialization to a static method on the cache. This is a small step towards making this functionality non-static and instead injected like normal members - however, completely removing all of the static-ness at once was too large of a change.

Instead document and add unit tests and change existing code as little as possible.

#47161

There have been some more additional reports of a missing 'package:characters' import after upgrading flutter. This has me concerned that our pub caching logic is incorrect. Instead of the tool attempting to guess when pub should be run, always delegate to pub.

Also takes an opportunity to fix the kernel snapshot depending on the .packages or package_config. Due to the generated: date field this causes extra rebuilds. Instead when pub get is run, write out an additional file with just the package contents and version.

Fixes #66777
Fixes #65723

Remove "This is taking a long time" progress timeout and TimeoutConfiguration.

All of the network requests from google cloud storage include an x-goog-hash header which contains an MD5 checksum. If present, use to validate that the downloaded binary is valid. This will rule out corrupt files as the cause of getting started crashers in the flutter_tool.

#38980

This does not fully resolve the above issue, because while we can check if the checksum matches what was expected from cloud storage, this A) may not necessarily be present and B) may not match up to what should be uploaded as part of the engine build process.

But when life gives you lemons you hash those lemons using an outdated hashing algorithm.

HACKTOBERFEST

This reverts commit 76cbc462.

There have been some more additional reports of a missing 'package:characters' import after upgrading flutter, as well as problems with detecting the correct language version. This has me concerned that our pub caching logic is incorrect. Instead of the tool attempting to guess when pub should be run, always delegate to pub.

[flutter_tools] handle case where file is deleted by other program or running on read only volume (#66708)

* [flutter_tools] handle case where file is deleted by other program

* Add test cases

* Update file_system.dart

* Update file_system_test.dart

* fix import

* make a static on ErrorHandligFS

* add support for no exit on failure

* address comments

* update doc comment to file or directory

Any File-derived IOSink may throw un-handleable async exceptions into the zone, see dart-lang/sdk#43663 . Instead, just write to a file with an append mode.

Otherwise the heuristics we have may decide to skip running pub. We should consider reducing the number of dimensions of caching here to a single check optimized for the run/test case.

Delete the destination directory for the web sdk before copying the new contents. This might fix an error where the OS refuses to overwrite the files on dev

[flutter_tools] use flutter tool handler for dwds resources and precache tool pub dependencies (#65814)

If the tool is downloaded from a precompiled snapshot, or if the backing source files in the pub cache are deleted, the dwds debugging functionality will break as the client.js file cannot be located. Instead use the PackageConfig to verify that package location, downloading if it is missing.

Override the dwds middleware to avoid Isolate.resolvePackageUri

Fixes #53644
Fixes #65475

Like the ProcessException thrown from zip running on a bad file, the tool should catch the ArchiveException thrown from windows implementation using package:archive.

Because the Status spinner was only created on setup, the second stop would asset/crash.

Fixes #65449

Exit the tool after a repeated network error to download. previously we were returning null and continuing on, leading to a ProcessException when we unzipped a missing file.

Fixes #64246

If decoding the string contents of a stamp file fails, treat it as if the stamp file is missing. This is always safe to do, since at worst it downloads more artifacts. The files could end up corrupted if they were edited by another program, for example

* Add punctuation for unterminated sentences in doc comments

* Addressing review nit

Add feature flags for android, ios, and fuchsia (on by default). After updating the g3 rollers, the fuchsia feature will be turned off by default. Creates a simpler base type of feature flags for g3 to extend.

Updates android, ios, fuchsia workflows to use feature flags check.
Removes concept of stable artifacts and checks on flutter version.

Fixes #58999
#52859
#12768