Introduce public PlatformHandle type

Adds mojo/public/cpp/platform to the public library. This includes
a new PlatformHandle type, a thin C++ abstraction for platform-specific
scoped handle values.

This is a precursor to moving platform channel C++ types out of the EDK
and into the public library, and ultimately introducing a public C++
invitation API to replace the EDK invitation API.

Bug: 844764
Change-Id: I317decc1deb8cc47eb1000a6a19022465c392d7b
Reviewed-on: https://chromium-review.googlesource.com/1068688
Reviewed-by: Jay Civelli <jcivelli@chromium.org>
Commit-Queue: Ken Rockot <rockot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560866}

CrOS-Libchrome-Original-Commit: 1bdfba5826e27ff0812b0a6011c4bca6ff3a73c1
6 files changed
tree: b6f3c99bc37a087c794c4ca0260016939d449b5c
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/