Previously [most of] the components were either in `widget` or depended on it,
and all theme-related resources (attributes, styles, etc.) were placed there.
This structure doesn't really work for our goals, and makes it harder to split
components by functional area. In this commit, I move all the theme definitions
to `theme` (as well as `dialog` and `bottomsheet` since they also have relevant
themes, and splitting them into separate packages is the only way to make the
dep tree non-circular). Component packages declare their own theme attributes
(e.g. `chip` declares all the theme attributes necessary for chips), as well as
styles, colors, dimens, drawables, etc.
This move isn't entirely complete in this commit, but it is enough to get
things building with this setup. I'll move the rest of the components' resources
in follow-up commits.
PiperOrigin-RevId: 182611275
Bazel is happier if Java/Java test roots are named 'java' and 'javatests', and
this will mean that once we create a BUILD file for
android/support/design/{widget,internal}/ we'll no longer need a custom package
specified in our build (which tends to cause build problems that manifest quite
weirdly). This commit doesn't attempt to refactor the build at all yet, and is
just a pure move.
PiperOrigin-RevId: 178060739
