Support emoji variation selectors in system fallback on Mac
As mentioned in [0], PlatformFallbackFontForCharacter relies on
FontFallbackPriority value in order to retrieve a font with the correct
emoji presentation.
Currently, when FontFallbackPriority is kEmojiEmoji, Chrome is using
hardcoded "Apple Color Emoji" system fallback font on Mac. But for kText
emoji codepoints Mac system API might return the colored "Apple Color
Emoji" font even if there is a monochromatic system font with the
requested glyph. To prevent that we will always force a monochromatic
"Apple Symbols" system font as a substitute font for text presentation
emoji codepoints.
Added web tests to test system fallback for emoji default and text
default emoji variation sequences.
[0] https://crrev.com/c/5771131
Bug: 40628044
Change-Id: I6fd4711ffc705bee156d4f7c787a4ad6e7974736
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5771251
Reviewed-by: Dominik Röttsches drott@chromium.org
Commit-Queue: Munira Tursunova moonira@google.com
Cr-Commit-Position: refs/heads/main@{#1341573}