GitLab

Optimization part 2.5 of ~3

In ShapeRunsWithFont, identify runs that the same initial CommonParams
and insert them into a RunVector. Change the rest of the shaping
pipeline to operate on these RunVectors, and move most of the
processing of CommonParams to be done once per RunVector instead of
once per run.

This change was intended to be part of the change to allow coalescing
of similar calls into HarfBuzz (which may or may not land), but it was
found to improve the performance in the cache hit case by a factor of
almost 2.

Bug: 862773
Change-Id: I8df02c2a8622eb9be74a65191fad79613ff1da2d
Reviewed-on: https://chromium-review.googlesource.com/1145904
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Leonard Grey <lgrey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577330}