GitLab

This CL has main goal to remove calls to the FontLink (GDI) fallback
fonts.

ShapeRuns is trying to find fonts to shape runs. There are cases where
the runs are grouped together but they can be rendered with different
fonts.

Previously, we were trying to determine the fallback font based on the
text of the first run, which is arbitrary. We observed cases where this
is not true.

As an example:
  // The following text will be split in 3 runs:
  //   1) u+1F3F3 u+FE0F u+FE0F  (Segoe UI Emoji)
  //   2) u+0020                 (Segoe UI)
  //   3) u+1F308 u+20E0 u+20E0  (Segoe UI Symbol)

The current CL is adding a loop around GetFallback(...) to find the
corresponding fallback font for each run using the fast fallback
mechanism. We believe this may deprecate the usage of the FontLink code.

R=robliao@chromium.org,asvitkine@chromium.org
CC=​drott@chromium.org

Bug: 995789
Change-Id: Iced98fa37f20832d7c86c107472e9fb84ec9d277
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1789844Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Dominik Röttsches <drott@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697243}