Fix PepperPortAllocator to resolve STUN addresses using HostResolverPrivate.

remoting/client/plugin/pepper_port_allocator.h

Index: remoting/client/plugin/pepper_port_allocator.h
diff --git a/remoting/client/plugin/pepper_port_allocator.h b/remoting/client/plugin/pepper_port_allocator.h
index 214cea53dc1e2c533c0e9b6edb673292168b50cd..c9a5dbde0658d08e8cf87e2e7a4eff792dc32f2a 100644
--- a/remoting/client/plugin/pepper_port_allocator.h
+++ b/remoting/client/plugin/pepper_port_allocator.h
@@ -13,9 +13,14 @@
 namespace remoting {
 
 // An implementation of cricket::PortAllocator for libjingle that is
-// used by the client plugin. The main difference from
-// cricket::HttpPortAllocator is that it uses Pepper URLLoader API
-// when creating relay sessions.
+// used by the client plugin. There are two differences from
+// cricket::HttpPortAllocator:
+//   * PepperPortAllocator uses Pepper URLLoader API when creating
+//     relay sessions.
+//   * PepperPortAllocator resolves STUN DNS names and passes IP
+//     addresses to BasicPortAllocator (it uses HostResolverPrivate API
+//     for that). This is needed because libjingle's DNS resolution
+//     code doesn't work in sandbox.
 class PepperPortAllocator : public cricket::HttpPortAllocatorBase {
  public:
   static scoped_ptr<PepperPortAllocator> Create(