[caching] Add WebAssembly cache

- Modifies Mojo code caching API to specify JS or WASM cache.
- Adds WebAssembly GeneratedCodeCache.

Bug: chromium:719172
Change-Id: Ie7dec8112a8e6cea7c576e2e502683bba0bb3d4a
Reviewed-on: https://chromium-review.googlesource.com/1235283
Commit-Queue: Bill Budge <bbudge@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595107}
21 files changed