This converts all remaining "## Sample code" segments into snippets, and fixes
the snippet generator to handle multiple snippets in the same dartdoc block
properly.
I also generated, compiled, and ran each of the existing application samples,
and fixed them up to be more useful and/or just run without errors.
This PR fixes these problems with examples:
1. Switching tabs in a snippet now works if there is more than one snippet in
a single dartdoc block.
2. Generation of snippet code now works if there is more than one snippet.
3. Contrast of text and links in the code sample block has been improved to
recommended levels.
4. Added five new snippet templates, including a "freeform" template to make
it possible to show examples that need to change the app instantiation.
5. Fixed several examples to run properly, a couple by adding the "Scaffold"
widget to the template, a couple by just fixing their code.
6. Fixed visual look of some of the samples when they run by placing many
samples inside of a Scaffold.
7. In order to make it easier to run locally, changed the sample analyzer to
remove the contents of the supplied temp directory before running, since
having files that hang around is problematic (only a problem when running
locally with the `--temp` argument).
8. Added a `SampleCheckerException` class, and handle sample checking
exceptions more gracefully.
9. Deprecated the old "## Sample code" designation, and added enforcement for
the deprecation.
10. Removed unnecessary `new` from templates (although they never appeared in
the samples thanks to dartfmt, but still).
Fixes#26398Fixes#27411
This adds support for logical and physical key information inside of RawKeyEvent. This allows developers to differentiate keys in a platform-agnostic way. They are able to tell the physical location of a key (PhysicalKeyboardKey) and a logical meaning of the key (LogicalKeyboardKey), as well as get notified of the character generated by the keypress. All of which is useful for handling keyboard shortcuts.
This PR builds on the previous PR (#27620) which generated the key code mappings and definitions.
This adds a keycode generator that incorporates input from the Chromium and Android source trees, as well as some local tables, to generate static constants for the LogicalKeyboardKey and PhysicalKeyboardKey classes, as well as mappings from each of the platforms we support so far (currently only Android and Fuchsia).
This code generator parses the input files, generates an intermediate data structure (`key_data.json`) that is checked in, and then generates the Dart sources for these classes and some static maps that will also be checked in (but are not included in this PR).
The idea is that these codes don't change often, and so we don't need to generate them on every build, but we would like to be able to update them easily in the future if new data becomes available. If the existing data disappears or becomes unusable, we can maintain the checked-in data structure by hand if necessary, and still be able to generate the code.
This PR only contains the code generator, not the classes themselves. In another follow-on PR, I'll run the generator and check in the output of the generator.
