* Use `curly_braces_in_flow_control_structures` for `packages/flutter_driver`

* Use `curly_braces_in_flow_control_structures` for `packages/flutter_goldens`

* Use `curly_braces_in_flow_control_structures` for `packages/flutter_goldens_client`

* Use `curly_braces_in_flow_control_structures` for `packages/flutter_localizations`

* Use `curly_braces_in_flow_control_structures` for `packages/flutter_test`

* Use `curly_braces_in_flow_control_structures` for `packages/flutter_web_plugins`

* fix comments

* Use `curly_braces_in_flow_control_structures` for `packages/integration_test`

* fix indentation

This reverts commit 5fd259be.

This reverts commit 5f792ba1.

This reverts commit 35ad43f2.

This reverts commit c26ed03c.

* Migrate to ChannelBuffers.push

* Move TestDefaultBinaryMessenger to its own file

* Apply deprecations and fix usages

This reverts commit 515ef91b.

- Remove `LogicalKeyboardKey.keyLabel`
- Make `Physical/LogicalKeyboardKey.debugName` getters
- Make `Physical/LogicalKeyboardKey()` factory constructors, which cache non-predefined instances.

* Added RawKeyEvent support for iOS

* Removed unused remnant

* added some missing keys

* Removed trailing whitespaces

* commit for build

* Added mapping names

* Made iOS keycodes generatable and collectable

* Fixed naming and formatting issues

* fixed raw_keyboard_test

- - When I added notification of key events before processing them as text, it made it so that shortcut key bindings like the spacebar would prevent spaces from being inserted into text fields, which is obviously not desirable (and so that change was reverted). At the same time, we do want to make it possible to override key events so that they can do things like intercept a tab key or arrow keys that change the focus.

This PR changes the behavior of the Shortcuts widget so that if it has a shortcut defined, but no action is bound to the intent, then instead of responding that the key is "handled", it responds as if nothing handled it. This allows the engine to continue to process the key as text entry.

This PR includes:

- Modification of the callback type for key handlers to return a KeyEventResult instead of a bool, so that we can return more information (i.e. the extra state of "stop propagation").
- Modification of the ActionDispatcher.invokeAction contract to require that Action.isEnabled return true before calling it. It will now assert if the action isn't enabled when invokeAction is called. This is to allow optimization of the number of calls to isEnabled, since the shortcuts widget now wants to know if the action was enabled before deciding to either handle the key or to return ignored.
- Modification to ShortcutManager.handleKeypress to return KeyEventResult.ignored for keys which don't have an enabled action associated with them.
- Adds an attribute to DoNothingAction that allows it to mark a key as not handled, even though it does have an action associated with it. This will allow disabling of a shortcut for a subtree.

Fix the `character` field of the `RawKeyEvent` to hold correct data on non-Android platforms. (#65667)

This fixes a problem where the character field of the RawKeyEvent was not being set at all for non-Android platforms.

I also updated the key maps, and corrected a problem with the Windows key map where the backquote character wasn't correctly mapped.

This standardizes the handling of nullability for the LogicalKeyboardKey.keyLabel and RawKeyEventData.keyLabel accessors so that they are non-nullable, but can be empty.

Before this change, the keyLabel could be either null or an empty string to indicate that there wasn't a label, which makes it harder to test for, since both need to be checked for. Since an empty string is sufficient, there is no need for it to be nullable.

Also, in raw_keyboard.dart, the web and Windows implementations wouldn't accept null values for parameters in the Map coming from the message, but tests were supplying null for some of them. This makes web and Windows creation of events match the other platforms, and makes the migration of tests to non-nullability easier.