Cache SkPromiseImageTexture

SkPromiseImageTexture is valid as long as the metadata does not
change (e.g. side, pixel format, texture ID).

This is true for the lifetime of a SharedImage. SharedImages are reused
by renderers as part of their cc::ResourcePool. Caching saves some
work for Skia during SkiaRenderer compositing.

Change-Id: I67b6f6f138509096e2b3ec2a3cc1555e00bd23f6
Bug: 914521
Reviewed-on: https://chromium-review.googlesource.com/c/1418735
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jonathan Backer <backer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623960}
3 files changed