commit 1aa788c1f3c5f356b4e06110b5780a1de99c4cd7
author morrita <morrita@chromium.org> Sat Jan 31 05:45:42 2015
committer Commit bot <commit-bot@chromium.org> Sat Jan 31 05:47:43 2015
tree acbbb590d3c776180f6a0d1204f44ceda33058c0
parent f61604541419bac129d2cd88b3d42039f6014161

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}