Pre-allocate space for single run fRunsInVisualOrder.

Most lines have one run in them, so avoid extra allocations in this
case. As a side effect, mark TextLine as moveable but not mem-movable.

The TextLine class used to be used as a mem-movable class, but the
addition of an SkSTArray made it non-mem-movable. Correct this and make
TextLine moveable and document its non-copyable nature. This avoids
ASAN use after free issues.

Change-Id: Icf45a464004e9f270ec46e1c2ddcf29fd356c90a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/292441
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Julia Lavrova <jlavrova@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2 files changed