* 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

There has been some confusion about whether or not
.flutter-plugins-dependencies should be tracked in version control or
not. Added a comment to both it and .flutter-plugins explaining that
it's generated and shouldn't be.

.flutter-plugins-dependencies is parsed through JSON, and the JSON spec
doesn't support comments. So unfortunately the note is living in an
arbitrary "_info" key instead of an obvious top level comment.

* implicit-casts:false on flutter_tools

* use castStringKeyedMap

* address review comments

* address review comments

* fix issues after rebase

Add `.flutter-plugins-dependencies` to the project, which contains the app's plugin dependency graph (#45379)

* implicit-casts:false on flutter_tools/lib

* address review comments

* use castStringKeyedMap

* introduce {bool,string,strings}Arg

* fix ci

One deprecated member was no longer used; removed it.

The other probably shouldn't be deprecated, because it's not the
parser that's deprecated so much as the format it's parsing. The code
itself will live on until we decide to stop supporting the format,
it's not like people calling the member should use something else.

This missed some plugins that _do_ support the v1 embedding
(shared_preferences as one known case) so caused unexpected breakages.

This reverts commit b94c1a41.

* Don't html-escape in the plugin registrant templates.

Fixes #43382

* Add test

* Generate projects using the new Android embedding

* Add comment about usesNewEmbedding:true

* Feedback

* Rework way to detect new embedding in new apps

* add missing trailing commas

* add more missing trailing commas

* add more and more missing trailing commas

Adds very preliminary support for Windows and Linux plugins:
- Adds those platforms to the new plugin schema, initially supporting just a plugin class.
- Adds C++ plugin registrant generation for any Windows or Linux plugins found.

This doesn't have yet have any build tooling for either platform, so anyone using the generated registrant still needs to do manual build configuration. This reduces the manual work, however, and creates a starting point for future tooling work.

As with all Windows and Linux work at this time, this is not final, and subject to change without warning in the future (e.g., Windows could potentially switch to a C# interface, or
'linux' may change to 'gtk' or 'linux_gtk' in pubspec.yaml).

When the plugin list changes, iOS pods are invalidated, but that was
never wired up for macOS.

Should fix #39327

Make FlutterPluginRegistrant a static framework so add-to-app can use plugins with static frameworks (#40401)

swift-format will alphabetize import statements, so Flutter* should be
before Foundation. Also, separating the "Generated file" comment
prevents the formatter from thinking that the comment is associated with
the following import, rather than the file, if it does re-order.

* WIP on web plugin registry

* WIP on registering plugins

* WIP on web plugin registration

* Only generate `package:flutter_web_plugins` imports if plugins are
defined

* Add parsing test

* Add documentation

* Fix analyzer warnings

* add license headers

* Add tests for package:flutter_web_plugins

* Run `flutter update-packages --force-upgrade`

* Fix analyzer errors

* Fix analyzer error in test

* Update copyright and remove flutter SDK constraints

* Enable tests since engine has rolled

* add flutter_web_plugins tests to bots

* Create an empty .packages file for WebFs test

This reverts commit bd52a78c.

Instead of sharing the iOS codepath that uses an ObjC generated plugin
registrant and expecting plugins to have an ObjC interface layer, switch
to generating a Swift registrant and expecting plugins to have a Swift
interface.

This means plugins on macOS that use Swift won't need an ObjC wrapper,
and plugins that use ObjC will need a Swift wrapper (inverting the
structure relative to iOS).

Enables the CocoaPods-based plugin workflow for macOS. This allows a
macOS project to automatically fetch and add native plugin
implementations via CocoaPods for anything in pubspec.yaml, as is done
on iOS.

Splits Xcode validation out of the iOS validator and into a stand-alone
validator, and groups the CocoaPods validator with that top-level
validator instead of the iOS validator. iOS now validates only the
iOS-specific tools (e.g., ideviceinstaller).

Reorganizes many of the associated clases so that those that are used by
both macOS and iOS live in macos/ rather than ios/. Moves some
validators to their own files as part of the restructuring.

This is the macOS portion of #31368

Adds a new macosPrefix, which serves the same purpose as iosPrefix but
for macOS plugins.

It is not yet used by the tooling, but this allows for plugins to start
to be written using it in preparation for tooling support for plugins.

Part of #32718