Add support for ProxyResolverErrorObserver to ProxyResolverMojo.

net/proxy/mojo_proxy_resolver_factory.h

Index: net/proxy/mojo_proxy_resolver_factory.h
diff --git a/net/proxy/mojo_proxy_resolver_factory.h b/net/proxy/mojo_proxy_resolver_factory.h
index eaf2774e800bd9ab874967eed0164642823d79f7..8a1143514d4a39e72f338657c22b4230744e09ee 100644
--- a/net/proxy/mojo_proxy_resolver_factory.h
+++ b/net/proxy/mojo_proxy_resolver_factory.h
@@ -17,8 +17,10 @@ class MojoProxyResolverFactory {
   // Connect to a new ProxyResolver service using request |req|, using
   // |host_resolver| as the DNS resolver.
   // Note: The connection request |req| may be resolved asynchronously.
-  virtual void Create(mojo::InterfaceRequest<interfaces::ProxyResolver> req,
-                      interfaces::HostResolverPtr host_resolver) = 0;
+  virtual void Create(
+      mojo::InterfaceRequest<interfaces::ProxyResolver> req,
+      interfaces::HostResolverPtr host_resolver,
+      interfaces::ProxyResolverErrorObserverPtr error_observer) = 0;
 
  protected:
   virtual ~MojoProxyResolverFactory() = default;