* 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
* Added new ButtonBarTheme to replace the deprecated ButtonTheme.bar method.
* Responding to PR feedback.
* [Material] Create material Banner component (#36880)
This PR creates a new material widget for the Banner component. This includes a theme as well. This widget can be dropped into any application, ideally at the top of a listview or scrollview.
(cherry picked from commit 35b6d668e197035ea2b57adb99041542982e8be0)
Removed the use of ButtonTheme.bar in the Banner implementation.
* Updated documentation from PR review comments.
