Remove unused locking functionality from base::SharedMemory.

The only existing consumers of the locking functionality were two unit tests for
SharedMemory.

The first unit test only tested the locking functionality across threads, so I
removed the test.

The second unit test was intended to test cross-process functionality of
base::SharedMemory, and used the locking functionality as a synchronization
method between processes. I rewrote the test to actually test Shared Memory
functionality, as the original test only tested synchronization between
processes, and would have succeeded even if Shared Memory didn't work. I
replaced the synchronization with compare and swap operations.

BUG=466437, 345734

Review URL: https://codereview.chromium.org/1167863002

Cr-Commit-Position: refs/heads/master@{#335135}


CrOS-Libchrome-Original-Commit: 893dadc6e82a64c8135b6f4852ee0960ea62e4a5
3 files changed
tree: 82e3bb2b305be88903c1aa6a8297258add406666
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/