ipc: Write end-to-end tests for SharedMemoryHandle brokering on Mac.

ipc/ipc_channel_posix.cc

Index: ipc/ipc_channel_posix.cc
diff --git a/ipc/ipc_channel_posix.cc b/ipc/ipc_channel_posix.cc
index e9c2ab0e50689b6f2def642faeab1eb971598bfe..51461e813df5c76e0fb1a484d8ae531ae74d1833 100644
--- a/ipc/ipc_channel_posix.cc
+++ b/ipc/ipc_channel_posix.cc
@@ -698,8 +698,8 @@ bool ChannelPosix::ProcessMessageForDelivery(Message* message) {
   if (message->HasBrokerableAttachments()) {
     DCHECK(GetAttachmentBroker());
     DCHECK(peer_pid_ != base::kNullProcessId);
-    for (const BrokerableAttachment* attachment :
-         message->attachment_set()->PeekBrokerableAttachments()) {
+    for (BrokerableAttachment* attachment :
+         message->attachment_set()->GetBrokerableAttachments()) {
       if (!GetAttachmentBroker()->SendAttachmentToProcess(attachment,
                                                           peer_pid_)) {
         delete message;