* Adds user account header arrow animation and test

https://github.com/flutter/engine/compare/70a1106b509e...22fc02028306

git log 70a1106b509e..22fc02028306 --no-merges --oneline
22fc02028 Roll src/third_party/skia fa8898747551..5d58d09ae77d (4 commits) (flutter/engine#6796)
d372d56ae Roll src/third_party/skia 23d1f94faac1..fa8898747551 (1 commits) (flutter/engine#6794)
8f105d79c Roll src/third_party/skia 2f8889b876d3..23d1f94faac1 (1 commits) (flutter/engine#6793)
0ce31d660 Roll src/third_party/skia 71bcc7d63f8c..2f8889b876d3 (1 commits) (flutter/engine#6792)
09ff6dc47 avoid overreleasing FlutterView (flutter/engine#6791)
bd793c011 Roll src/third_party/skia f49563bf9276..71bcc7d63f8c (3 commits) (flutter/engine#6790)
c8da28826 Roll Dart version to 9c07fb64c48adb3d6fde50bab6b8b641c5b67683 (flutter/engine#6788)
94dd7165e Skia Cleanup (flutter/engine#6786)
547b8585e Roll src/third_party/skia b52c273d3f05..f49563bf9276 (7 commits) (flutter/engine#6785)
b6f76e07a Delete unused license goldens and add check (flutter/engine#6784)


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* clarify widgetsapp docs

* Rename shadowed param, update doc

* pageContentBuilder

Reverts flutter/flutter#24111 as https://skia-review.googlesource.com/c/buildbot/+/167200 has been deployed.

We need to wait the fix in
https://skia-review.googlesource.com/c/buildbot/+/169724
to land in order to enable the rebase merge method again.

TBR: goderbauer

We'll land this quickly without waiting for presubmit checks
to unblock our engine roller.

* Move integration tests to use vm_service_lib
* Turn off debug logging that was accidentally committed
* Run update-packages --force to fix checksum for new dev dependency
* Trim trailing whitespace

This converts existing ## Sample code samples to {@tool sample}...{@end-tool} form.

Also:
1. Fixed a minor bug in analyze-sample-code.dart
2. Made the snippet tool only insert descriptions if the description is non-empty.
3. Moved the Card diagram to before the code sample.

* Document module pubspec

* update doc on plugin template

* clarify language

We have templates now.

https://github.com/flutter/engine/compare/2494abdda728...70a1106b509e

git log 2494abdda728..70a1106b509e --no-merges --oneline
70a1106b5 Unify copyright lines (flutter/engine#6757)
f9095fcc4 Roll src/third_party/skia 62cc5f581747..b52c273d3f05 (13 commits) (flutter/engine#6783)
4cdddbac4 Fix String comparison as if Java were Dart. (flutter/engine#6781)


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* Removes need for homebrew installation if all other packages are installed. Modifies test to work with this new functionality.

Also, remove old flags.

In order for this to take effect, https://skia-review.googlesource.com/c/buildbot/+/167200
needs to be landed and deployed.

The /bin/internal/engine.merge_method file controls how we merge a pull
request created by the engine auto-roller. If it's squash, there's only one
commit for a pull request no matter how many engine commits there are inside
that pull request. If it's rebase, the number of commits in the framework is
equal to the number of engine commits in the pull request. The latter method is
easier to detect regressions but cost more test resources.

* Include framework version in JSON output and adds test

* adds fix for rounding error

* update assert add test

* update docs

https://github.com/flutter/engine/compare/e64af7510e89...2494abdda728

git log e64af7510e89..2494abdda728 --no-merges --oneline
2494abdda Roll src/third_party/skia 273fa2f3bd0b..62cc5f581747 (7 commits) (flutter/engine#6780)
daeeedafa Roll src/third_party/skia 67f5c0ceac22..273fa2f3bd0b (1 commits) (flutter/engine#6779)


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Should fix #22226.

Code introduced in #20890 caused a regression that broke color flooding animations in a BottomNavigationBar that has BottomNavigationBarType.shifting.

The original issue (#19653) dealt with background color changes not occurring until another tab was selected. The result is that the background color instantly changes whenever the state changes and when the widget changes, instead of allowing a new widget to animate the background color change.

When converting all of the samples to use the snippet tool, I encountered some bugs/shortcomings:

1. The document production took 90 minutes, since the snippet tool was being invoked from the command line each time. I fixed this by snapshotting the executable before running, so it's down to 7 minutes.

2. The sample code was not being properly escaped by the snippet tool, so generics were causing issues in the HTML output. It is now quoted.

3. Code examples that used languages other than Dart were not supported. Anything that highlight.js was compiled for dartdoc with is now supported.

4. The comment color for highlight.js was light grey on white, which was pretty unreadable. It's now dark green and bold.

https://github.com/flutter/engine/compare/824daacf6d95...e64af7510e89

git log 824daacf6d95..e64af7510e89 --no-merges --oneline
e64af7510 Roll src/third_party/skia 2a13921745eb..67f5c0ceac22 (2 commits) (flutter/engine#6777)


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https://github.com/flutter/engine/compare/4f4c470d2419...824daacf6d95

git log 4f4c470d2419..824daacf6d95 --no-merges --oneline
824daacf6 Roll src/third_party/skia 3daed9b12db4..2a13921745eb (1 commits) (flutter/engine#6776)


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

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* early return for initialRoute + test

https://github.com/flutter/engine/compare/e61f05256eaa...4f4c470d2419

git log e61f05256eaa..4f4c470d2419 --no-merges --oneline
4f4c470d2 Roll src/third_party/skia 630e7d651a34..3daed9b12db4 (6 commits) (flutter/engine#6775)
177e043b5 fix setInitialRoute (flutter/engine#6774)
6fa5c0a82 Pass scriptCode into Locale on initialization. (flutter/engine#6711)

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https://github.com/flutter/engine/compare/dda667f8f093...e61f05256eaa

git log dda667f8f093..e61f05256eaa --no-merges --oneline
e61f05256 Roll src/third_party/skia 2aa9a22fe159..630e7d651a34 (5 commits) (flutter/engine#6773)
21eb1caae Update the contributing guide (flutter/engine#6754)

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dda667f8f Roll update to harfbuzz to 2.1.0 (#6760)
e8f0c08c9 Add instructions to download the full license log diff. (#6771)
5077e95f1 Roll src/third_party/skia f2b35e4fb8cc..2aa9a22fe159 (7 commits) (#6770)

* Improves error message and adds test.

5006ce574 fix type in embedded views preview flag name (flutter/engine#6767)
eec27fc8a Roll src/third_party/skia e70c6b13dd55..f2b35e4fb8cc (6 commits) (flutter/engine#6768)
aea7071e2 Roll src/third_party/skia e6c85755832b..e70c6b13dd55 (1 commits) (flutter/engine#6766)
1132d6c42 Roll src/third_party/skia 11407e56f277..e6c85755832b (2 commits) (flutter/engine#6765)