Refactored PairingRegistry::Delegate such that it can retrieve/modify for a single client.

remoting/host/pairing_registry_delegate.cc

Index: remoting/host/pairing_registry_delegate.cc
diff --git a/remoting/host/pairing_registry_delegate.cc b/remoting/host/pairing_registry_delegate.cc
index ada8cfcfe86f5ee7753a6ca34e5b2e37fba78f88..c7e49a0ddbd4d16badb54828690f228c3e98d22d 100644
--- a/remoting/host/pairing_registry_delegate.cc
+++ b/remoting/host/pairing_registry_delegate.cc
@@ -4,19 +4,19 @@
 
 #include "remoting/host/pairing_registry_delegate.h"
 
-#include "base/task_runner.h"
+#include "base/single_thread_task_runner.h"
 
 namespace remoting {
 
 using protocol::PairingRegistry;
 
 scoped_refptr<PairingRegistry> CreatePairingRegistry(
-    scoped_refptr<base::TaskRunner> task_runner) {
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
   scoped_refptr<PairingRegistry> pairing_registry;
   scoped_ptr<PairingRegistry::Delegate> delegate(
-      CreatePairingRegistryDelegate(task_runner));
+      CreatePairingRegistryDelegate());
   if (delegate) {
-    pairing_registry = new PairingRegistry(delegate.Pass());
+    pairing_registry = new PairingRegistry(task_runner, delegate.Pass());
   }
   return pairing_registry;
 }