[ribbon] Don't generate CSSProperty.

The CSSProperty class itself has no generated code, hence it does not
make sense that it's "generated".

This CL moves the CSSProperty class to regular files.

The global GetCSSFoo()-functions previously generated at the end of
css_property.h.tmpl are now provided directly by css_property_instances.
This eliminates the "Internal" set of global functions, which it turns out
we don't really need.

(correctly) complained that they did not belong in css_property.h.

Note: Some forward declarations had to be moved, because a presubmit check
Change-Id: I8a66371498013defd02443b47c1954f49f576585
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1506793
Commit-Queue: Anders Hartvoll Ruud <andruud@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Reviewed-by: Xida Chen <xidachen@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640696}
15 files changed