Make utility process run in-process when running in single-process mode.

ipc/ipc_channel_proxy.cc

Index: ipc/ipc_channel_proxy.cc
===================================================================
--- ipc/ipc_channel_proxy.cc	(revision 210446)
+++ ipc/ipc_channel_proxy.cc	(working copy)
@@ -210,6 +210,9 @@
 
 // Called on the IPC::Channel thread
 void ChannelProxy::Context::OnRemoveFilter(MessageFilter* filter) {
+  if (!channel_.get())
+    return;  // The filters have already been deleted.
+
   for (size_t i = 0; i < filters_.size(); ++i) {
     if (filters_[i].get() == filter) {
       filter->OnFilterRemoved();