Clean up public interface of AttachmentBrokerUnprivileged.

In the old interface, a static factory method returns a scoped_ptr, and the
caller had to manage the lifetime. Since this is a global object with minimal
memory footprint, and is required to outlive every IPC::Channel, it's much
easier for the global to never be destroyed. This also matches the interface for
AttachmentBrokerPrivileged.

BUG=584297

Committed: https://crrev.com/11fea2242b3a197993dbd5a1f977f9a31c6b98e4
Cr-Commit-Position: refs/heads/master@{#375674}

Review URL: https://codereview.chromium.org/1679763002

Cr-Commit-Position: refs/heads/master@{#375776}


CrOS-Libchrome-Original-Commit: 8666287a9b42256b20692765f43c12a960398699
6 files changed
tree: 5b05ea3e2352cd0c4fe39c18a375315723fccb3a
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/