GitLab

Adds Blink mojo Remote/Receiver wrappers HeapMojo{Receiver,Remote}
Also uses them in the speech module as an example

Design doc:
https://docs.google.com/document/d/1mYKbNgVzQUbc0zKLjiBcO5Ue_VTh3sIwj8glHU-azQ8/edit

Bug: 1049056
Change-Id: Ia14f455736197f25d1fdbfe78473d3681fd02e37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2000268
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742032}