ppapi: Add methods for sharing new shared memory classes with remote

This CL adds two new methods, ShareUnsafeSharedMemoryRegionWithRemote() and
ShareReadOnlySharedMemoryRegionWithRemote() to
ppapi::proxy::ProxyChannel::Delegate and to content::RendererPpapiHost classes
and all implementation classes.

These new methods are similar to the SharedSharedMemoryHandleWithRemote()
method in those classes but are supposed to work with the new shared memory
API.

Bug: 845985
Change-Id: I8ccd92a1c81dca9495c85119e9a4e40fd6b69abf
Reviewed-on: https://chromium-review.googlesource.com/1078847
Commit-Queue: Alexandr Ilin <[email protected]>
Reviewed-by: Antoine Labour <[email protected]>
Reviewed-by: Raymes Khoury <[email protected]>
Cr-Commit-Position: refs/heads/master@{#563571}
16 files changed