RPHI::AddRoute: Turn a DCHECK() to a CHECK() again.

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 cbfa1504dcc45c3da2c9ca022ee9573df0cdd2de..ebc142890d975e7c2469e8a0fed4b813ffcc9016 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -921,8 +921,10 @@ ServiceRegistry* RenderProcessHostImpl::GetServiceRegistry() {
 void RenderProcessHostImpl::AddRoute(
     int32 routing_id,
     IPC::Listener* listener) {
-  DCHECK(widget_helper_->IsRoutingIDProbablyValid(routing_id))
-      << "Found Routing ID conflicts: " << routing_id;
+  CHECK(widget_helper_->IsRoutingIDProbablyValid(routing_id))
+      << "Found Invalid Routing ID: " << routing_id;
+  CHECK(!listeners_.Lookup(routing_id))
+      << "Found Routing ID Conflict: " << routing_id;
   listeners_.AddWithID(listener, routing_id);
 }