* Initial work

* ++

* Updated tests

* Moved TestObserver out for access across tests.

* ++

* Added hero tests

* Review feedback

* simplified preceding route overlay

* Review feedback

* trailing doc slash

* Add missing [applicationIcon] property to LicensePage widget

For https://github.com/flutter/flutter/issues/31086.

Also test if our mac8 with iPhone XS is working
(https://github.com/flutter/flutter/issues/34590).

https://github.com/flutter/engine/compare/3c51a7bfff77...e695a516f148

git log 3c51a7bfff776e9e3011384f4ff09c13a697c6b6..e695a516f148cef9c7850a6e00151f00bfadf0d4 --no-merges --oneline
e695a516f Add FLEDartProject for macOS embedding (flutter/engine#9672)
44f2f07ff Roll src/third_party/skia e192c4ce5a33..829b6a0ff49f (1 commits) (flutter/engine#9705)
d5f15d1cd Roll src/third_party/skia de6758683abd..e192c4ce5a33 (2 commits) (flutter/engine#9703)
e46532986 Roll src/third_party/skia 2f62edf1ac5d..de6758683abd (1 commits) (flutter/engine#9700)
05966cd14 Roll src/third_party/skia 1d105080c423..2f62edf1ac5d (1 commits) (flutter/engine#9699)
b132baa44 Ensure that platform messages without response handles can be dispatched. (flutter/engine#9698)
50d622857 fix Picture.toImage return type check and api conform test. (flutter/engine#9685)
001bb541c Roll src/third_party/skia 8063f6cca025..1d105080c423 (3 commits) (flutter/engine#9692)
db4d6836a Roll src/third_party/skia 857c9f955edb..8063f6cca025 (3 commits) (flutter/engine#9679)

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 (jsimmons@google.com), and stop
the roller if necessary.

* Fix "the a" typos

* Rephrase global key API doc description

* Introduce image_list performance benchmark that runs on jit(debug) build.

We want to track performance of debug build because ongoing work on reducing the cost of spanwing new isolate will impact jit(debug) more than it will aot(release) configurations.

* Newlines and spaces

An upcoming change in the Dart SDK changes `Socket` from
implementing `Stream<List<int>>` to implementing `Stream<Uint8List>`.
This forwards-compatible change in flutter_tools prepares for that
Dart SDK change.

https://github.com/dart-lang/sdk/issues/36900

https://github.com/flutter/engine/compare/7d3e722349e7...3c51a7bfff77

git log 7d3e722349e7923115f0b8800022a08c8dd795b3..3c51a7bfff776e9e3011384f4ff09c13a697c6b6 --no-merges --oneline
3c51a7bff Roll src/third_party/skia 11eb847a2080..857c9f955edb (2 commits) (flutter/engine#9676)
7f828dd3e Raster now returns an enum rather than boolean (flutter/engine#9661)
11b6afe00  Roll src/third_party/dart 67ab3be10d...b5aeaa6796 (flutter/engine#9675)
3c4dbe223 Revert " Roll src/third_party/dart 67ab3be10d...43891316ca (#9670)" (flutter/engine#9673)
5e596f2ac  Roll src/third_party/dart 67ab3be10d...43891316ca (flutter/engine#9670)
46a2239b4 Roll src/third_party/skia 5b52c52141ac..11eb847a2080 (6 commits) (flutter/engine#9671)
b84f89b44 Allow embedders to add callbacks for responses to platform messages from the framework. (flutter/engine#9655)
8dac2e979 Begin separating macOS engine from view controller (flutter/engine#9654)
d3616c7a3 Roll src/third_party/skia 0e0113dcbd9a..5b52c52141ac (8 commits) (flutter/engine#9665)
cea2c3617 Mutators Stack refactoring (flutter/engine#9663)
6a8782fe0 Roll src/third_party/skia 93eeff578b08..0e0113dcbd9a (9 commits) (flutter/engine#9662)
791143f17 ExternalViewEmbedder can CancelFrame after pre-roll (flutter/engine#9660)
d637f291a External view embedder can tell if embedded views have mutated (flutter/engine#9653)
ceee3d733 Roll src/third_party/skia 38ae3f42fec1..93eeff578b08 (1 commits) (flutter/engine#9659)
d75729006 Roll src/third_party/skia febc162c7898..38ae3f42fec1 (3 commits) (flutter/engine#9658)
58133abce Roll src/third_party/skia 3de5c6388142..febc162c7898 (2 commits) (flutter/engine#9657)
29342dd30 Roll src/third_party/skia 1e2cb444e0c1..3de5c6388142 (8 commits) (flutter/engine#9656)
b5473560d Pipeline allows continuations that can produce to front (flutter/engine#9652)
8306ee68c Move the mutators stack handling to preroll (flutter/engine#9651)
511b9f23a Roll src/third_party/skia 215ff3325230..1e2cb444e0c1 (12 commits) (flutter/engine#9650)

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 (jsimmons@google.com), and stop
the roller if necessary.

This is necessary for those who wish to comply with static analysis like
`strict-raw-types: true`, which includes generated code within their package.

CupertinoTextField now supports vertical alignment via the textAlignVertical parameter.

Marking it as experimental was breaking tests and packaging
scripts on stable branches.

https://github.com/flutter/engine/compare/ffba2f68d4e8...7d3e722349e7

git log ffba2f68d4e8ec2041f57226d907dcb929c8b795..7d3e722349e7923115f0b8800022a08c8dd795b3 --no-merges --oneline
7d3e72234 Roll buildroot to c5a493b25. (flutter/engine#9649)
8deeb77f0 make EmbeddedViewParams a unique ptr (flutter/engine#9640)
7862af546 Roll src/third_party/skia bd3d8d39b3e7..215ff3325230 (4 commits) (flutter/engine#9648)
a9ee687ac iOS PlatformView clip path (flutter/engine#9478)
c19b53cf2 Roll src/third_party/skia effee2065796..bd3d8d39b3e7 (1 commits) (flutter/engine#9647)
aeaa5edee Roll src/third_party/skia 2ef826576819..effee2065796 (1 commits) (flutter/engine#9646)
1cc1f04c9 Roll src/third_party/skia f2c52efce52b..2ef826576819 (2 commits) (flutter/engine#9645)
1c295b226 Roll src/third_party/skia 9fb7fa537d93..f2c52efce52b (1 commits) (flutter/engine#9644)
56a3f4102 Android Embedding Refactor PR31: Integrate platform views with the new embedding and the plugin shim. (flutter/engine#9206)
8ac7cbdda Fix warning about settings unavailable GN arg build_glfw_shell (flutter/engine#9642)
f66571781 Roll src/third_party/skia 21a486d04ae0..9fb7fa537d93 (21 commits) (flutter/engine#9639)
fd24007ca Roll Dart to 67ab3be10d35d994641da167cc806f20a7ffa679 (flutter/engine#9638)
628b174c9 Fixes a plugin overwrite bug in the plugin shim system. (flutter/engine#9589)
345d350ab Added Doxyfile. (flutter/engine#9632)
64b9eef5c Revert "Roll Dart to 67ab3be10d35d994641da167cc806f20a7ffa679 (#9634)" (flutter/engine#9637)
45e1ad274 Roll Dart to 67ab3be10d35d994641da167cc806f20a7ffa679 (flutter/engine#9634)
da6475eec Roll fuchsia/sdk/core/mac-amd64 from TRwIGIJLuznLNQzJk17zfboJrkErpe1XvGr0njCwemoC to byM-kyxL4bemlTYNqhKUfJfZoIUrCSzS6XzsFr4n9-MC (flutter/engine#9629)
bee12e6f3 Roll fuchsia/sdk/core/mac-amd64 from MBS_xxNZ_O32DxW1bhOeJisJqYG9JY_FAtSa3ZYupg4C to TRwIGIJLuznLNQzJk17zfboJrkErpe1XvGr0njCwemoC (flutter/engine#9626)
fea8fa6c4 Roll fuchsia/sdk/core/linux-amd64 from Efv1uHDvhLYgT8mvQmdAiJv7HiLix2L_kDRkK6P9ER4C to I2Qe1zxgckzIzMBTztvzeWYsDgcb9Fw-idSI16oIlx8C (flutter/engine#9625)
e7f8ca1de [all] add fuchsia.{net.NameLookup,posix.socket.Provider} (flutter/engine#9546)
a72a9997e Roll fuchsia/sdk/core/mac-amd64 from B-JzM_H7hG5kOIRFjmUqI3uWBAV7no8BnCTknbd2wQ4C to MBS_xxNZ_O32DxW1bhOeJisJqYG9JY_FAtSa3ZYupg4C (flutter/engine#9624)
b3fe3e95d Fix a race in the embedder accessibility unit test (flutter/engine#9585)
55818f602 Roll fuchsia/sdk/core/linux-amd64 from xtoj1ola0unTQOetly-V77CgpT6g8L1JUKWDqS8SuAQC to Efv1uHDvhLYgT8mvQmdAiJv7HiLix2L_kDRkK6P9ER4C (flutter/engine#9623)
37a54f2ab Roll fuchsia/sdk/core/linux-amd64 from O1niQGtIRghvjuMMCmxevRA1Y6seUn6onOao6Wii9hQC to xtoj1ola0unTQOetly-V77CgpT6g8L1JUKWDqS8SuAQC (flutter/engine#9622)
458a7647a Roll fuchsia/sdk/core/mac-amd64 from neDu8hWotIrKCQkxz1ScSJC4NoBva1_YVszr6wMbcZQC to B-JzM_H7hG5kOIRFjmUqI3uWBAV7no8BnCTknbd2wQ4C (flutter/engine#9621)
6e7b4ca44 Roll fuchsia/sdk/core/linux-amd64 from gMVpYn1cxQ0LeU-TSryUCg2o3rNcf7JWvlOqY6G00MYC to O1niQGtIRghvjuMMCmxevRA1Y6seUn6onOao6Wii9hQC (flutter/engine#9620)
e4d354d2c Roll src/third_party/skia 161f47dfbf6a..21a486d04ae0 (2 commits) (flutter/engine#9619)
28028759b Roll fuchsia/sdk/core/mac-amd64 from tPyg8rqV40gsoXEhDf7VskccnbJGCh4_bZp71YOUinEC to neDu8hWotIrKCQkxz1ScSJC4NoBva1_YVszr6wMbcZQC (flutter/engine#9618)
8e405c1db Roll fuchsia/sdk/core/mac-amd64 from UkCx2sMZsCM-w9nEuQC2TRfnJ7wjJCxsCxSDEx2uPegC to tPyg8rqV40gsoXEhDf7VskccnbJGCh4_bZp71YOUinEC (flutter/engine#9615)
609a98060 Fix uninitialized variables and put tests in flutter namespace. (flutter/engine#9613)
9807894ac Roll fuchsia/sdk/core/linux-amd64 from ur0ah3sh2atct83EqYX28SjG3fKt-7Driu48GbpdxmMC to gMVpYn1cxQ0LeU-TSryUCg2o3rNcf7JWvlOqY6G00MYC (flutter/engine#9612)
4e344e6cd Wire up custom event loop interop for the GLFW embedder. (flutter/engine#9089)
54c62263d Roll fuchsia/sdk/core/mac-amd64 from gyWAjP3BPfhpvHOOwaTusfA8JaGcY_UzjpoIGQnA_W0C to UkCx2sMZsCM-w9nEuQC2TRfnJ7wjJCxsCxSDEx2uPegC (flutter/engine#9611)
c3f8cab29 Roll fuchsia/sdk/core/linux-amd64 from xmxDtsnD0sfj7wxUaiMMhUwh72prBvMcYHY07lgTotcC to ur0ah3sh2atct83EqYX28SjG3fKt-7Driu48GbpdxmMC (flutter/engine#9610)
6f1a748ae Document various classes in //flutter/shell/common. (flutter/engine#9591)
4d3653092 Roll fuchsia/sdk/core/mac-amd64 from 4PD6FCl4NvKCavA0AVsdKtZPB3G5K72KprkEH0mr064C to gyWAjP3BPfhpvHOOwaTusfA8JaGcY_UzjpoIGQnA_W0C (flutter/engine#9609)
cf084bdb6 Roll fuchsia/sdk/core/linux-amd64 from XRYatTY5OvCnQ-5rGC8AnYltKa68CBxmnEK8QO0fpvQC to xmxDtsnD0sfj7wxUaiMMhUwh72prBvMcYHY07lgTotcC (flutter/engine#9607)
8d054008a disable mysterious failing tests (flutter/engine#9608)
aa817a9a2 Roll fuchsia/sdk/core/mac-amd64 from DeTFBSaxMBfZpfK0c7CifGpJbJLOrs3WtuCOaINwmrwC to 4PD6FCl4NvKCavA0AVsdKtZPB3G5K72KprkEH0mr064C (flutter/engine#9606)
4e988e0ae Roll fuchsia/sdk/core/linux-amd64 from jXpdljb7CHe8PEpUGGYqGvx6vFar6QRUh6HmpxMoS9sC to XRYatTY5OvCnQ-5rGC8AnYltKa68CBxmnEK8QO0fpvQC (flutter/engine#9605)
84ae36ac2 Roll fuchsia/sdk/core/mac-amd64 from IMr36r3rRLs1G7T5OtCudVMoWjPcjRbYGgyDg7LSxPwC to DeTFBSaxMBfZpfK0c7CifGpJbJLOrs3WtuCOaINwmrwC (flutter/engine#9604)
7135c8dbd Roll fuchsia/sdk/core/mac-amd64 from qcwCYvuT0PeU97HpvMVmC114EOKwfrk8PdFdZz_m6CIC to IMr36r3rRLs1G7T5OtCudVMoWjPcjRbYGgyDg7LSxPwC (flutter/engine#9602)
8f4df037b Roll fuchsia/sdk/core/linux-amd64 from Y3kUPtfq2frI60zx7VssO-WG733jtODCmnESyz0UGdEC to jXpdljb7CHe8PEpUGGYqGvx6vFar6QRUh6HmpxMoS9sC (flutter/engine#9601)
6c6a0d753 [trace clients] Remove fuchsia.tracelink.Registry (flutter/engine#9593)
f931539b2 Roll fuchsia/sdk/core/mac-amd64 from UsrGfX7Fj96MljgqUFc_A-o_ufsa_FX3eaG14ZSDWMAC to qcwCYvuT0PeU97HpvMVmC114EOKwfrk8PdFdZz_m6CIC (flutter/engine#9600)
...