IPC::Message Refactoring: Move POSIX specific bits to PlatformFileAttachment
This change:
* Gets rid of MessageAttachmentSet::owning_descriptors_ by moving
the responsibility to PlatformFileAttachment, where owning_
member variable is used to track the lifetime
* Replaces MessageAttachmetnSet::Add*File() and TakePlatformFile()
with platform agnostic AddAttachment() and GetAttachmentAt()
* Repalces Message::ReadFile(), Write*File() with ReadAttachment()
and WriteAttachmente(), which are also platform agnostic.
This also adds MessageAttachment::TakePlatformFile() virtual function,
which will be implemented by upcoming MojoHandleAttachment as well.
This is another preparation for introducing MojoHandleAttachment,
but it also simplifies Message and MessageAttachmentSet.
R=agl@chromium.org
TBR=mtomasz@chromium.org
BUG=448190
Review URL: https://codereview.chromium.org/883093003
Cr-Commit-Position: refs/heads/master@{#314047}
CrOS-Libchrome-Original-Commit: 1aa788c1f3c5f356b4e06110b5780a1de99c4cd7
13 files changed