Split out coretext fontmgr factory.

There can be only one SkFontMgr::Factory, so each should go in its own
translation unit. In addition, the name SkFontHost_mac is now rather out
of date and should now be SkFontMgr_mac_ct. Since the additional burden
of additional build changes after the first is minimal, also split out
SkTypeface_mac_ct and SkScalerContext_mac_ct. The original
SkFontHost_mac.cpp is kept as a shell which #includes the cpp files
which are replacing it. Once references to it are removed from all
builds it can be removed.

This is intended to be a reorganization without much code change. Most
changes are simple renaming of functions which are now shared between
translation units. However, there are a few behavior changes here.
  * Drop SkTypefaceCache global for SkTypeface_Mac 'local' global.
  * SkCTFontCTWidthForCSSWidth returns CGFloat instead of 'int'.
  * SkFontMgr_New_CoreText takes a CTFontCollectionRef.

Change-Id: Iac548f9fd920c426ea5c6dcdefe8da0a9b89ec90
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294456
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294704
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294714
Reviewed-by: Ben Wagner <bungeman@google.com>
15 files changed