* 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 adds support for game controller buttons. It adds some supplemental USB HID codes that aren't available from the Chromium source code, and maps those on Android to the game pad buttons that Android supports. Other platforms are not supported yet.
This implements the keyboard shortcut handling and action invocation in order to provide a place in the infrastructure for keyboard events to trigger actions. This will allow binding of key events to actions like "move the focus to the next widget" and "activate button".
This adds a list of key synonyms for non-printable keyboard keys that appear in more than one place So keys like LogicalKeyboardKey.shiftLeft and LogicalKeyboardKey.shiftRight now can be mapped to just LogicalKeyboardKey.shift.
I also fixed a bug in the gen_keycodes tool where GLFW entries would get removed if they weren't parsed from the source on the web.