* doc update

This switches the Cirrus macOS images to use Mojave, since Cirrus has deprecated the High Sierra images.

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

* fix some formatting issues

* address review comments

* fix indent

flutter/engine@f4951df19 (upstream/master) Minor cleanups to CONTRIBUTING.md (flutter/engine#8043)
flutter/engine@effee2f80 remove extra statement (flutter/engine#8041)
flutter/engine@14e082fa0 (master) add lint script for Android with baseline (flutter/engine#8036)
flutter/engine@5fed42197 Roll src/third_party/skia 25bc174cf682..72542816cadb (14 commits) (flutter/engine#8040)
flutter/engine@e6a5201f0 Add missing values to semantics action enums (flutter/engine#8033)
flutter/engine@75d4db31d Roll src/third_party/skia fbc887df72ec..25bc174cf682 (7 commits) (flutter/engine#8039)
flutter/engine@c46226980 Roll src/third_party/skia 0a57971f0544..fbc887df72ec (1 commits) (flutter/engine#8037)
flutter/engine@ed628da00 Add missing kHasImplicitScrolling enum value (flutter/engine#8030)
flutter/engine@052774e1c Roll src/third_party/skia e3e80b7edfd1..0a57971f0544 (16 commits) (flutter/engine#8035)
flutter/engine@2cd9b41ba Select MPL instead of LGPL (flutter/engine#7991)
flutter/engine@629c0d836 Roll src/third_party/dart 7d8ffe0daf..571ea80e11 (3 commits)
flutter/engine@8f1fdcd19 Android Embedding PR 14: Almost done with FlutterFragment. (flutter/engine#8000)
flutter/engine@fb3e35d6a Android Embedding PR15: Add Viewport Metrics to FlutterView (flutter/engine#8029)
flutter/engine@36ca5740c (flutter/engine#8026)
flutter/engine@3d53e2026 Roll src/third_party/skia 5800f2e8a920..e3e80b7edfd1 (2 commits) (flutter/engine#8028)
flutter/engine@f3d4a7f71 Roll src/third_party/dart 7c70ab1817..7d8ffe0daf (77 commits)
flutter/engine@a2246c199 Start of linting Android embedding (flutter/engine#8023)
flutter/engine@48bf4803e [fuchsia] Fix snapshot BUILD.gn file for Fuchsia roll (flutter/engine#8024)

When a touch event that is in the bounds of a RenderUiKitView is absorbed by another render object,
the RenderUiKitView's handleEvent is not called for that object. On the platform side, the touch event hits the FlutterTouchInterceptingView which is waiting for a framework decision that never arrived on whether to reject or accept the gesture.

This change fixes the issue by having RenderUiKitView register a global PointerRoute, that is used to reject absorbed touch events.

* Added code snippets for FloatingActionButton Class. ref:#21136

* Extraneous white spaces.
Co-Authored-By: Piinks <katelovett@google.com>

* Alignment correction.

* The analyze result wasn't showing on github interface. Checked through Cirrus and it's all-green.
Co-Authored-By: Piinks <katelovett@google.com>

Use a simpler implementation of Diagnosticable.toString when running in profile/release mode (#28661)

Diagnosticable.toString may be called in performance sensitive contexts
(for example, creating debug labels for Tickers)

This function is called frequently with non-repeating images during many
animations

This change permits
(1) a relative --flutter-shell
(2) relative (source, dill) entries within the test JSON file

and enables portability in the invocation scripts produced by fuchsia's
dart test GN template.

https://github.com/flutter/engine/compare/e9eae9a1af77...4f54a1dd9444

git log e9eae9a1af77400d02c498f0ad943f2858845398..4f54a1dd944497bd1ec0f2acca22ff9fbd8b377a --no-merges --oneline
4f54a1dd9 Roll src/third_party/skia c1a9feb6f06e..5800f2e8a920 (2 commits) (flutter/engine#8022)
75e2b4702 Roll src/third_party/skia c6671be0ea75..c1a9feb6f06e (2 commits) (flutter/engine#8021)
b44a9305c Roll src/third_party/skia 1b9f889628e0..c6671be0ea75 (1 commits) (flutter/engine#8020)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (garyq@google.com), and stop
the roller if necessary.

e9eae9a1a Roll src/third_party/skia c97b0672a73f..1b9f889628e0 (1 commits) (flutter/engine#8019) (#28801)


https://github.com/flutter/engine/compare/a28329cb91ac...e9eae9a1af77

git log a28329cb91ac18ad4d7950b3b170a74a8de979ee..e9eae9a1af77400d02c498f0ad943f2858845398 --no-merges --oneline
e9eae9a1a Roll src/third_party/skia c97b0672a73f..1b9f889628e0 (1 commits) (flutter/engine#8019)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (garyq@google.com), and stop
the roller if necessary.

https://github.com/flutter/engine/compare/39c46dea4b73...a28329cb91ac

git log 39c46dea4b7347a252218aaff5caac5dc2fec8cd..a28329cb91ac18ad4d7950b3b170a74a8de979ee --no-merges --oneline
a28329cb9 Roll src/third_party/skia 58a75383a70b..c97b0672a73f (1 commits) (flutter/engine#8018)
cdc141072 Roll src/third_party/skia 0d7012a80c17..58a75383a70b (1 commits) (flutter/engine#8017)
01d8a1f27 Roll src/third_party/skia c945f0e31a53..0d7012a80c17 (1 commits) (flutter/engine#8016)
75cd4df37 Roll src/third_party/skia 9159c8ef83b2..c945f0e31a53 (1 commits) (flutter/engine#8015)
13064aec8 Add overloads for lookup that lets you specify a bundle (flutter/engine#8007)
130cf77c5 Build engine for iOS on presubmit (flutter/engine#8011)
7234cc463 Roll src/third_party/skia 705e67347962..9159c8ef83b2 (1 commits) (flutter/engine#8014)
8a0b054a4 Roll src/third_party/skia 09198525261a..705e67347962 (7 commits) (flutter/engine#8013)
36cdd2ee6 Roll src/third_party/skia 436d47d5bde9..09198525261a (6 commits) (flutter/engine#8012)
9bef73a1a Roll src/third_party/skia e1f5b644656f..436d47d5bde9 (3 commits) (flutter/engine#8009)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (garyq@google.com), and stop
the roller if necessary.

https://github.com/flutter/engine/compare/66042161eba1...39c46dea4b73

git log 66042161eba17da968800c57ddd2c314cd787abb..39c46dea4b7347a252218aaff5caac5dc2fec8cd --no-merges --oneline
39c46dea4 Revert "Buffer lifecycle in WindowData (#7999)" (flutter/engine#8010)
293cfcaa5 Guard against using Android API not defined in API level 16 & 17 (flutter/engine#8006)
d7e0bc10c Roll src/third_party/skia 71a23d4195d9..e1f5b644656f (8 commits) (flutter/engine#8004)
0b1740171 Buffer lifecycle in WindowData (flutter/engine#7999)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

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the roller if necessary.

* Added code snippet for Expanded class. ref:#21136

* Changed the code samples into snippet application samples.

@xster

* Add curve fastInFastOut

* Rename it to slowCenter

* Rename to slowMiddle

* Add continuous test

When we package Flutter, we used to find the "current" tag (which is the version number) by starting at the revision we are building on and looking backwards in time to find the most recent tag. This causes problems on release builds when we failed to tag properly.

This PR makes the packaging script be more strict by requiring the given revision to itself have a tag, but only when we're publishing the result. When we're not publishing the result, it's more lenient, since otherwise we couldn't test packaging on non-release commits.

I also renamed ProcessRunnerException to PreparePackageException, since we were using that exception more generally than just for processes.

66042161e Roll src/third_party/skia 255569187f27..71a23d4195d9 (1 commits) (flutter/engine#8003) (#28731)


https://github.com/flutter/engine/compare/99f3f7a9c246...66042161eba1

git log 99f3f7a9c246f1ebedc6eefd867cde250b370380..66042161eba17da968800c57ddd2c314cd787abb --no-merges --oneline
66042161e Roll src/third_party/skia 255569187f27..71a23d4195d9 (1 commits) (flutter/engine#8003)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (garyq@google.com), and stop
the roller if necessary.

When pub fails, log the %ERRRORLEVEL% to help diagnose the root cause of
the pub failure.

* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

flutter/engine@99f3f7a9c Fix incorrect transformation matrix (flutter/engine#8001)
flutter/engine@c88b09710 Roll src/third_party/skia b7b2da871e95..255569187f27 (23 commits) (flutter/engine#8002)
flutter/engine@302e2e9d2 Fix cursor jumping when typing some special characters. (flutter/engine#7964)
flutter/engine@fe15149d1 Android Embedding PR 12: Add lifecycle methods to FlutterActivity. (flutter/engine#7974)
flutter/engine@6145e9046 Android Embedding PR 13: Integrated text input, keyevent input, and some other channel comms in FlutterView. (flutter/engine#7979)

## Description

This moves another 15-20ms from the animation jank of one of our important client to the startup latency. Unfortunately, this is probably not captured in our current benchmarks (presumably some other bottlenecks overshadow this shader compilation in the worst_frame benchmark). Considering that drawing images is such a common operation, maybe we should add one in the future to benchmark this.

We need this PR to land soon for our client because this changes the API to return Future.

## Related Issues

https://github.com/flutter/flutter/issues/813

See https://github.com/flutter/flutter/pull/28614#discussion_r261422778
and https://github.com/flutter/flutter/pull/28614#pullrequestreview-209359908

https://github.com/flutter/engine/compare/5194919e1309...56c16154eada

git log 5194919e130917d29ac15f0ac7f52ea94d1a4d67..56c16154eadada5f77c57ddca39a86c5e30c5768 --no-merges --oneline
56c16154e Android Embedding PR 9: Introduce an AndroidTouchProcessor to convert MotionEvents to Flutter touch data. (flutter/engine#7947)
a1d84996d Fix spelling errors in dartdocs (flutter/engine#7997)
6bc9c3d17 Roll src/third_party/dart 40bab34fbd..7c70ab1817 (35 commits)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (garyq@google.com), and stop
the roller if necessary.

Fix the spelling errors in the dartdocs for the framework.

There are no functionality changes here, just documentation fixes.

One of our important client's SKP shows that this could improve one of
their janky frame by 20ms. This also improves our
flutter_gallery__transition_perf's worst frame time by ~20ms.

On the other hand, 15ms has been added to the start-up latency. I guess
it's a little faster to compile the shader on the start-up because we're
compiling a lot of shaders there and the CPU cache must be hot.

## Related Issues

https://github.com/flutter/flutter/issues/813