ipc: Use a global for the process's attachment broker.

ipc/attachment_broker.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ipc/attachment_broker.h"
 
 #include <algorithm>
 
+namespace {
+IPC::AttachmentBroker* g_attachment_broker = nullptr;
+}
+
 namespace IPC {
 
+// static
+void AttachmentBroker::SetGlobal(AttachmentBroker* broker) {
+  CHECK(!g_attachment_broker);
+  g_attachment_broker = broker;
+}
+
+// static
+AttachmentBroker* AttachmentBroker::GetGlobal() {
+  return g_attachment_broker;
+}
+
 AttachmentBroker::AttachmentBroker() {}
 AttachmentBroker::~AttachmentBroker() {}
 
 bool AttachmentBroker::GetAttachmentWithId(
     BrokerableAttachment::AttachmentId id,
     scoped_refptr<BrokerableAttachment>* out_attachment) {
   for (AttachmentVector::iterator it = attachments_.begin();
        it != attachments_.end(); ++it) {
     if ((*it)->GetIdentifier() == id) {
       *out_attachment = *it;
@@ skipping 25 matching lines @@
 void AttachmentBroker::NotifyObservers(
     const BrokerableAttachment::AttachmentId& id) {
   // Make a copy of observers_ to avoid mutations during iteration.
   std::vector<Observer*> observers = observers_;
   for (Observer* observer : observers) {
     observer->ReceivedBrokerableAttachmentWithId(id);
   }
 }
 
 }  // namespace IPC