Just a few remaining references to Skia types like SkScalar and
SkSize/Rect. After this most of Impeller is Skia-free except for areas
that deal with fonts, images, and the `toolkit/interop` and
`typographer` directories.

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

Just a few remaining references to Skia types like SkScalar and
SkSize/Rect. After this most of Impeller is Skia-free except for areas
that deal with fonts, images, and the `toolkit/interop` and
`typographer` directories.

…#170494)

…#170494)

…#170494)

…#170494)

…#170494)

referred to the following commits:
    c0db033("[Impeller] Remove use of simple Skia objects (flutter#170494)")
    37736df("Migrate surface frame shell code to DisplayList/Impeller geometry classes (flutter#173086)")

But this only makes the host build finished with the following commands:
    $ ./flutter/tools/gn --unoptimized --no-prebuilt-dart-sdk --full-dart-sdk
    $ ninja -C out/host_debug_unopt

and the execution of out/host_debug_unopt/impeller_unittests crashed

Also the necessary changes for ohos directories are not touched yet.
it will be done when doing the target side build

Signed-off-by: Yongqin Liu <[email protected]>