{Add,Get}Interface() for PendingAssociatedReceiver/AssociatedRemote

This comes from the discussion of crrev/c/1306240. We want to migrate
- AssociatedInterfaceRequest to PendingAssociatedReceiver.
- AssociatedInterfacePtr to AssociatedRemote

However AssociatedInterfaceRegistry and AssociatedInterfaceProvider
don't have such support yet.

Bug: 955171
Change-Id: I350dba2dac66b37cfc59f08daa06b000352b0c1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1685837
Reviewed-by: Ken Rockot <[email protected]>
Reviewed-by: Arthur Sonzogni <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Commit-Queue: Shimi Zhang <[email protected]>
Cr-Commit-Position: refs/heads/master@{#675743}
5 files changed