* Update project.pbxproj files to say Flutter rather than Chromium
Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.
* Update the copyright notice checker to require a standard notice on all files
* Update copyrights on Dart files. (This was a mechanical commit.)
* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.
Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).
* Clean up the copyrights in non-Dart files. (Manual edits.)
Also, make sure templates don't have copyrights.
* Fix some more ORGANIZATIONNAMEs
* 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
* Bugfix: Add platformBrightness to TestWindow.
* Manual engine roll:
cc27cafb8 Implemented Dark Mode for Android (#25525) ([flutter/engine#7488](https://github.com/flutter/engine/pull/7488))
9c05cbcfb Roll src/third_party/dart b53dceadaa..5823be65af (5 commits) 5823be65af [vm/compiler] Continued graph checker development (reland) 8231cdb7a3 [gardening] Update status for issue 35854 db7f848632 [vm] Remove dead BigInt code. 35ab1755f4 Support more type propagation for code-as-ui features 569ee07f91 [vm] Cleanup class finalization checks
ec5e6f6ef Ensure dart2js and kernel worker snapshots are copied out of gen dir ([flutter/engine#7692](https://github.com/flutter/engine/pull/7692))
8b5fa65c4 Roll src/third_party/skia 50ea3c06b80f..2d35a1c87553 (6 commits) ([flutter/engine#7693](https://github.com/flutter/engine/pull/7693))
