This reverts commit eb0b1790.
Skia Gold post-submit test were failing due to the service account not being found on Cirrus.

* Fresh PR for Gold integration.

* Nits

* WIP

* Artifacts from merge

* Changed some platform dependencies for web, added library prefix notation for Skia Gold test names.

* Updating for CI implementation

* Write out service account

* Writing to skip out

* WIP

* ++

* Fixing depot tools deps

* Windows depot_tools

* Fixing setup scripts

* ++

* depot tools

* ++

* WIP

* Tracing depot_tools clone

* WIP

* ++

* analyzer

* WIP

* chrome typo

* copy artifact

* Working on tests

* Code cleanup

* ++

* Code cleanup, updated tests

* ++ review feedback

* Review

* Analyzer

* Review feedback

* Nits from review

* PRogress

* ++

* Fixing tests

* ++

* Testing repo route

* Just needing documention around new structures.

* cleanup

* Analyzer

* Documentation updates

* Documentation updates

* Cirrus updates

* cirrus nit

* Review feedback

* Review feedback

* Fixing skip comparator

* Fix base directory for Skia Gold case

* ++

* Feedback

* ++

* Fixed uri assertion

* Made GoldensClient abstract, altered SkiaGoldClient constructor

* Analyzer

Corects a bnuch of typeos throuhgout teh Fluter codebsae.

Made use of the `misspell` tool:
https://github.com/client9/misspell

Revert "Merge branch 'master' into master"

This reverts commit e3a03c04, reversing
changes made to 64749826.

Changed implementation to incorpoarate new init feature for goldctl. Reduces redundant work as well.

When running git update-packages, if the goldens repo is dirty, the
flutter tool currently crashes and logs the failure from git pull.

This adds a check for a dirty git client and emits a friendlier error
message in the case where it's not clean, and avoid the crash by
catching the NonZeroExitCode exception and rethrowing as toolExit
instead.

Fixes: https://github.com/flutter/flutter/issues/28915

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

flutter_tools cannot depend on flutter_goldens (as flutter_goldens
depdends on the Flutter sdk), so this commit splits client.dart from
flutter_goldens to a pure-dart flutter_goldens_client package.