IPC: Fix attachment brokering race condition.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index cf27a0f299a3cc98667a3dec0d15530d1f3a4e46..b8231b918dd1ad75a82a869f0547e0598290ce78 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -728,11 +728,6 @@ bool RenderProcessHostImpl::Init() {
   const std::string channel_id =
       IPC::Channel::GenerateVerifiedChannelID(std::string());
   channel_ = CreateChannelProxy(channel_id);
-#if USE_ATTACHMENT_BROKER
-  IPC::AttachmentBroker::GetGlobal()->RegisterCommunicationChannel(
-      channel_.get(), content::BrowserThread::GetMessageLoopProxyForThread(
-      content::BrowserThread::IO));
-#endif
 
   // Call the embedder first so that their IPC filters have priority.
   GetContentClient()->browser()->RenderProcessWillLaunch(this);
@@ -828,9 +823,15 @@ std::unique_ptr<IPC::ChannelProxy> RenderProcessHostImpl::CreateChannelProxy(
     }
 #endif  // OS_ANDROID
 
-    return IPC::ChannelProxy::Create(
-        IPC::ChannelMojo::CreateServerFactory(std::move(handle)), this,
-        runner.get());
+  std::unique_ptr<IPC::ChannelProxy> channel(
+      new IPC::ChannelProxy(this, runner.get()));
+#if USE_ATTACHMENT_BROKER
+  IPC::AttachmentBroker::GetGlobal()->RegisterCommunicationChannel(
+      channel.get(), content::BrowserThread::GetMessageLoopProxyForThread(
+      content::BrowserThread::IO));
+#endif
+  channel->Init(IPC::ChannelMojo::CreateServerFactory(std::move(handle)), true);
+  return channel;
   }
 
     // Do NOT expand ifdef or run time condition checks here! See comment above.
@@ -841,8 +842,15 @@ std::unique_ptr<IPC::ChannelProxy> RenderProcessHostImpl::CreateChannelProxy(
   }
 #endif  // OS_ANDROID
 
-  return IPC::ChannelProxy::Create(channel_id, IPC::Channel::MODE_SERVER, this,
-                                   runner.get());
+  std::unique_ptr<IPC::ChannelProxy> channel(
+      new IPC::ChannelProxy(this, runner.get()));
+#if USE_ATTACHMENT_BROKER
+  IPC::AttachmentBroker::GetGlobal()->RegisterCommunicationChannel(
+      channel.get(), content::BrowserThread::GetMessageLoopProxyForThread(
+      content::BrowserThread::IO));
+#endif
+  channel->Init(channel_id, IPC::Channel::MODE_SERVER, true);
+  return channel;
 }
 
 void RenderProcessHostImpl::CreateMessageFilters() {