Move attachment broker setup to browser startup.

content/common/child_process_host_impl.cc

Index: content/common/child_process_host_impl.cc
diff --git a/content/common/child_process_host_impl.cc b/content/common/child_process_host_impl.cc
index d69d5352a285f8a16065536a3f3708fc23f494e9..9654d1bcda54d1943a9e4f2feda32c7b165e4423 100644
--- a/content/common/child_process_host_impl.cc
+++ b/content/common/child_process_host_impl.cc
@@ -86,19 +86,6 @@ ChildProcessHostImpl::ChildProcessHostImpl(ChildProcessHostDelegate* delegate)
 #if defined(OS_WIN)
   AddFilter(new FontCacheDispatcher());
 #endif
-
-#if USE_ATTACHMENT_BROKER
-#if defined(OS_MACOSX) && !defined(OS_IOS)
-  // On Mac, the privileged AttachmentBroker needs a reference to the Mach port
-  // Provider, which is only available in the chrome/ module. The attachment
-  // broker must already be created.
-  DCHECK(IPC::AttachmentBroker::GetGlobal());
-#else
-  // Construct the privileged attachment broker early in the life cycle of a
-  // child process.
-  IPC::AttachmentBrokerPrivileged::CreateBrokerIfNeeded();
-#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
-#endif  // USE_ATTACHMENT_BROKER
 }
 
 ChildProcessHostImpl::~ChildProcessHostImpl() {
@@ -109,8 +96,11 @@ ChildProcessHostImpl::~ChildProcessHostImpl() {
     return;
 
 #if USE_ATTACHMENT_BROKER
-  IPC::AttachmentBroker::GetGlobal()->DeregisterCommunicationChannel(
-      channel_.get());
+  // In unit tests, the attachment broker may not have been initialized.
+  if (IPC::AttachmentBroker::GetGlobal()) {
+    IPC::AttachmentBroker::GetGlobal()->DeregisterCommunicationChannel(
+        channel_.get());
+  }
 #endif
   for (size_t i = 0; i < filters_.size(); ++i) {
     filters_[i]->OnChannelClosing();
@@ -135,8 +125,11 @@ std::string ChildProcessHostImpl::CreateChannel() {
   if (!channel_->Connect())
     return std::string();
 #if USE_ATTACHMENT_BROKER
-  IPC::AttachmentBroker::GetGlobal()->RegisterCommunicationChannel(
-      channel_.get());
+  // In unit tests, the attachment broker may not have been initialized.
+  if (IPC::AttachmentBroker::GetGlobal()) {
+    IPC::AttachmentBroker::GetGlobal()->RegisterCommunicationChannel(
+        channel_.get());
+  }
 #endif
 
   for (size_t i = 0; i < filters_.size(); ++i)