Add support for ProxyResolverErrorObserver to ProxyResolverMojo.

net/proxy/proxy_resolver_mojo.h

Index: net/proxy/proxy_resolver_mojo.h
diff --git a/net/proxy/proxy_resolver_mojo.h b/net/proxy/proxy_resolver_mojo.h
index 9d97095142479b2bd58d78d096efecd3d9e1c302..a4356a99a11e53e2b6cb3aaefb1a941cbc9cdfac 100644
--- a/net/proxy/proxy_resolver_mojo.h
+++ b/net/proxy/proxy_resolver_mojo.h
@@ -25,6 +25,7 @@ namespace net {
 class BoundNetLog;
 class HostResolver;
 class ProxyInfo;
+class ProxyResolverErrorObserver;
 class MojoProxyResolverFactory;
 
 // Implementation of ProxyResolver that connects to a Mojo service to evaluate
@@ -42,7 +43,8 @@ class ProxyResolverMojo : public ProxyResolver, public mojo::ErrorHandler {
   // and |host_resolver| are not owned and must outlive this.
   // TODO(amistry): Add ProxyResolverErrorObserver and NetLog.
   ProxyResolverMojo(MojoProxyResolverFactory* mojo_proxy_resolver_factory,
-                    HostResolver* host_resolver);
+                    HostResolver* host_resolver,
+                    scoped_ptr<ProxyResolverErrorObserver> error_observer);
   ~ProxyResolverMojo() override;
 
   // ProxyResolver implementation:
@@ -59,6 +61,7 @@ class ProxyResolverMojo : public ProxyResolver, public mojo::ErrorHandler {
 
  private:
   class Job;
+  class ErrorObserverHolder;
 
   // Overridden from mojo::ErrorHandler:
   void OnConnectionError() override;
@@ -91,6 +94,8 @@ class ProxyResolverMojo : public ProxyResolver, public mojo::ErrorHandler {
   // existing one disconnects (i.e. when utility process crashes).
   HostResolver* host_resolver_;
 
+  scoped_ptr<ErrorObserverHolder> error_observer_;
+
   std::set<Job*> pending_jobs_;
   net::CancelableCompletionCallback set_pac_script_callback_;