Child thread attachment broker should never be destroyed.

content/child/child_thread_impl.cc

Index: content/child/child_thread_impl.cc
diff --git a/content/child/child_thread_impl.cc b/content/child/child_thread_impl.cc
index 5378463a0cdade74433293961bfc4ece5b7aea4b..5ac7bcf38525d87634dde89c3ba437110c5d24e0 100644
--- a/content/child/child_thread_impl.cc
+++ b/content/child/child_thread_impl.cc
@@ -371,8 +371,9 @@ void ChildThreadImpl::Init(const Options& options) {
   // The only reason a global would already exist is if the thread is being run
   // in the browser process because of a command line switch.
   if (!IPC::AttachmentBroker::GetGlobal()) {
-    attachment_broker_.reset(
-        IPC::AttachmentBrokerUnprivileged::CreateBroker().release());
+    // Intentionally leak the attachment broker so that it is never destroyed.

[Avi (use Gerrit), 2016/02/06 07:03:40]

Mention _why_ you leak it, not just that you do.

+    attachment_broker_ =
+        IPC::AttachmentBrokerUnprivileged::CreateBroker().release();
   }
 #endif