This reverts commit 5f3f3bd9.

So we can do golden test on PerformanceOverlay to avoid regression like
https://github.com/flutter/flutter/issues/26387

- Moved versions from shell to common
- versions singleton contains all the required versions.

* Improve PathMetrics

* Use index instead of dirty

* revert unintended change

* space

Behavior (visual) changes should be very minor. Things that are to be expected:
* A few things were not color managed correctly by the transform canvas (color emoji, some color filters). Those will be handled correctly with the tagged surfaces (although we're always transforming to sRGB, so nothing should change until we target a wider gamut).
* Image filtering will happen in the source color space, rather than the destination. Very minor.
* The transform canvas did caching of images in the destination color space. Now, the conversion happens at draw time. If there are performance issues, images can be pre-converted to the destination with makeColorSpace().

Updates the test_fixtures rule to support a custom kernel output file
name. Improves rule documentation.

* Make IOManager own resource context

* fix up analysis for Dart in Engine, particularly for tests

* Reset ParagraphBuilder after build()

* Update GetCallbackHandle to use Dart_IsTearOff instead of a string
comparison to determine whether or not a closure was provided as an
argument to PluginUtilities.GetCallbackHandle.

Fixes #24394

As of the migration to Dart 2, it has been necessary to compile Dart to
kernel prior to execution. The embedder currently requires that the
resulting kernel file be named `kernel_blob.bin` and be located at the
root of the assets directory passed to the embedder API.

This patch updates the test_fixtures build rule to perform a kernel
compile using frontend_server, outputting `kernel_blob.bin` to
`fixtures/test_target_name` directory, and updates the embedder
unittests to specify the kernel file rather than the Dart source file.

Since the kernel compiler requires a `main()` function to be defined, it
also updates `simple_main.dart` from runtime_unittests to define
`main()` rather than `simple_main()`.

This also updates all existing sub-targets to be testonly.

This relands commit ac9e521a, which was
reverted in commit 49411258. Rather than
running as prebuilt_dart_action, we use dart_action to ensure the
frontend snapshot it compatible with the VM on which it's executed.

This reverts commit ac9e521a.

This broke dynamic release mode builds of
//flutter/runtime:runtime_fixtures_kernel (likely all product-mode
builds).

Compile embedder unit test Dart to kernel

As of the migration to Dart 2, it has been necessary to compile Dart to
kernel prior to execution. The embedder currently requires that the
resulting kernel file be named `kernel_blob.bin` and be located at the
root of the assets directory passed to the embedder API.

This patch updates the test_fixtures build rule to perform a kernel
compile using frontend_server, outputting `kernel_blob.bin` to
`fixtures/test_target_name` directory, and updates the embedder
unittests to specify the kernel file rather than the Dart source file.

Since the kernel compiler requires a `main()` function to be defined, it
also updates `simple_main.dart` from runtime_unittests to define
`main()` rather than `simple_main()`.

This also updates all existing sub-targets to be testonly.

* Roll back _countryCode assert - breaking change

* Add tests back in

* Add Locale.fromComponents.

* Change toString from underscores to dashes. Expand the unit tests.

* Rename 'fromComponents' to 'create'. Change variants from String to List<String>.

* Use default for language parameter. Use hashCode/hashList.

* Have toString() stick with old (underscore) behaviour.

* Demonstrate empty-list bug in assert code.

* Fix empty-list assert bug.

* Add ignores for lint issues. Unsure about 71340 though.

* Fix operator== via _listEquals.

* Remove length-checking asserts: we're anyway not checking characters in fields.

* Documentation update.

* Change reasoning for ignore:prefer_initializing_formals.

* Try 'fromSubtags' as new constructor name.

* Documentation improvements based on Pull Request review.

* Assert-fail for invalid-length subtags and drop bad subtags in production code.

* Revert "Assert-fail for invalid-length subtags and drop bad subtags in production code."

This reverts commit d6f06f5e7b3537d60000c47641580475ef16abbe.

* Re-fix Locale.toString() for variants=[].

* Tear out variants, in case we want to have one fewer pointer in the future.

* Make named parameters' names consistent with member names.

* Also remove _listEquals: no longer in use.

* Lint fix.

* Fix code review nits.

* Lint fix for assert, and a couple more not-zero-length-string asserts.

* Code Review: two of three nits addressed...

* Review fix: change 'should' to 'must' for subtag prescriptions.

* Assert-check that countryCode is never ''.

* Locale Passing

* Pass full locale list and script and variant codes to framework

* Working Android locale list passing and fallback

Provide a relative, per-image limit to the amount of memory
that's used to cache decoded image frames. Adds an overridable default
that developers can set to control how much memory images are allowed
to use decoded vs undecoded. The cap is set in flutter/flutter#22452.

Note that required frames are always cached regardless of the ratio cap,
because they're currently necessary for the GIF to animate. Previously
cached unessential frames are not cleared in response to the cache
hitting or exceeding the cap.

Addresses #20998 and #14344.

Updates the tests to use the `--use-test-fonts` argument.

Fixes flutter/flutter#22682

This replaces `ci/test.sh` with `run_tests.sh`. `run_tests.sh` includes
`ci/test.sh` and multiple other tests.

Partially addresses flutter/flutter#22682. Temporarily skipped tests
should be fixed and re-enabled in a follow-up commit.

It is now working properly on the bots.

`testing/dart/android/` and `testing/dart/ios` both look like generated
directories created after each `run_tests` execution.

This reflects that we no longer uses travis. Scripts are moved to ci folder.