Stub in more IPC attachment brokering functionality.

ipc/mojo/ipc_channel_mojo.cc

Index: ipc/mojo/ipc_channel_mojo.cc
diff --git a/ipc/mojo/ipc_channel_mojo.cc b/ipc/mojo/ipc_channel_mojo.cc
index 4886a125ee6a7fcab0b42a661d930b0977907bb8..e762ecc2deb4f2bf65a0bdf1660486b2729e44a0 100644
--- a/ipc/mojo/ipc_channel_mojo.cc
+++ b/ipc/mojo/ipc_channel_mojo.cc
@@ -554,8 +554,9 @@ MojoResult ChannelMojo::ReadFromMessageAttachmentSet(
                   attachment.get())->TakeHandle();
           handles->push_back(handle.release().value());
         } break;
-        case MessageAttachment::TYPE_WIN_HANDLE:
-          NOTREACHED();
+        case MessageAttachment::TYPE_BROKERABLE_ATTACHMENT:
+          // Brokerable attachments are handled by the AttachmentBroker so

[Tom Sepez, 2015/06/19 18:04:11]

Still need a NOTREACHED() here.

[erikchen, 2015/06/23 22:37:00]

Done.

+          // there's no need to do anything here.
           break;
       }
     }