Remove base::RefCountedSharedMemory (unused)

It is wrapping a deprecated class base::SharedMemory. All users of
base::RefCountedSharedMemory have been updated and this class is no
more used, it can be removed.

Chromium Shared Memory Refactor design doc:

Bug: 795291
Change-Id: I67a7fa8a6103fc0813171c0a0b5b2965809cef2c
Reviewed-by: Pavol Marko <>
Reviewed-by: Nico Weber <>
Commit-Queue: Arthur Sonzogni <>
Cr-Commit-Position: refs/heads/master@{#651177}
13 files changed