Remoting: upgrade remoting/host shared memory to new API.

Change implementation of webrtc::SharedMemory to use
base::UnsafeSharedMemoryRegion. Should not change any
functionality outside of changing a read-only mapping of
shared memory to be a const mapping, as the former is no
longer supported by the chromium shared memory API.

Remoting: upgrade remoting/host shared memory to new API.

Bug: 795291, 961119
Change-Id: Iff24e1a6fd780d6f6b1618f20a588dbd596541f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1602502
Commit-Queue: Matthew Cary <mattcary@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Alex Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663030}
5 files changed