Implement browser-side host resolver Mojo service.

net/dns/mojo_host_resolver_impl.h

Index: net/dns/mojo_host_resolver_impl.h
diff --git a/net/dns/mojo_host_resolver_impl.h b/net/dns/mojo_host_resolver_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..186d0da903f00d5ea3db3e9faf3b76492526aa6c
--- /dev/null
+++ b/net/dns/mojo_host_resolver_impl.h
@@ -0,0 +1,54 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_DNS_MOJO_HOST_RESOLVER_IMPL_H_
+#define NET_DNS_MOJO_HOST_RESOLVER_IMPL_H_
+
+#include <set>
+
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "net/interfaces/host_resolver_service.mojom.h"
+
+namespace net {
+
+class HostResolver;
+
+// This is the implementation of the HostResolver Mojo interface.
+// Inbound Mojo requests are sent to the HostResolver passed into the
+// constructor. When destroyed, any outstanding resolver requests are cancelled.
+// If a request's HostResolverRequestClient is shut down, the associated
+// resolver request is cancelled.
+class MojoHostResolverImpl
+    : public mojo::InterfaceImpl<interfaces::HostResolver> {

[jamesr, 2015/02/12 18:23:11]

InterfaceImpl is deprecated (hence the DEPRECATED warning in the header) so you
shouldn't use it in new code.  Inherit directly from interfaces::HostResolver
and use a mojo::Binding<> or mojo::StrongBinding<>

[Anand Mistry (off Chromium), 2015/02/12 22:54:09]

Oops. Actually, we do use Binding<>. Not sure why I put this here.

+ public:
+  // |resolver| is expected to outlive |this|.
+  explicit MojoHostResolverImpl(net::HostResolver* resolver);
+  ~MojoHostResolverImpl() override;
+
+ private:
+  class Job;
+
+  // Removes |job| from the set of pending jobs, and deletes it.
+  void DeleteJob(Job* job);
+
+  // Overridden from net::interfaces::HostResolver:
+  void Resolve(interfaces::HostResolverRequestInfoPtr request_info,
+               interfaces::HostResolverRequestClientPtr client) override;
+
+  // Resolver for resolving incoming requests. Not owned.
+  net::HostResolver* resolver_;
+
+  // All pending jobs, so they can be cancelled when this service is destroyed.
+  // Owns all jobs.
+  std::set<Job*> pending_jobs_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoHostResolverImpl);
+};
+
+}  // namespace net
+
+#endif  // NET_DNS_MOJO_HOST_RESOLVER_IMPL_H_