Generates the DTLS identity in browser process and returns it to render process.

content/renderer/media/dtls_identity_service.h

Index: content/renderer/media/dtls_identity_service.h
diff --git a/content/renderer/media/dtls_identity_service.h b/content/renderer/media/dtls_identity_service.h
new file mode 100644
index 0000000000000000000000000000000000000000..a6e13534d797533d30eb907c65e155e7ea3f65bc
--- /dev/null
+++ b/content/renderer/media/dtls_identity_service.h
@@ -0,0 +1,58 @@
+// Copyright (c) 2013 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 CONTENT_RENDERER_MEDIA_DTLS_IDENTITY_SERVICE_H_
+#define CONTENT_RENDERER_MEDIA_DTLS_IDENTITY_SERVICE_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/public/renderer/render_process_observer.h"
+#include "googleurl/src/gurl.h"
+
+namespace content {
+
+class RenderThread;
+
+// TODO (jiayl): Move it to Libjingle and implement it there.

[Ryan Sleevi, 2013/06/06 23:57:37]

It seems like these should happen before continuing this CL. Otherwise, the
design anti-patterns here (Observer vs base::Callback<>) make it hard to review.

+class DTLSIdentityObserver {
+ public:
+  virtual ~DTLSIdentityObserver() {}
+  virtual void OnCompleted(const std::string& certificate,
+                           const std::string& private_key) = 0;
+};
+
+// This class handles DTLS identity requests by sending IPC messages to the
+// browser process.
+// TODO: implement webrtc::DTLSIdentityServiceInterface from Libjingle.
+class DTLSIdentityService : public RenderProcessObserver {
+ public:
+  DTLSIdentityService(const GURL& origin,
+                      scoped_ptr<DTLSIdentityObserver>& observer);

[Ryan Sleevi, 2013/06/06 23:57:37]

BUG: Do not pass this as a non-const reference. Use

"scoped_ptr<DTLSIdentityObserver> observer"

This *forces* callers to be aware that they're transferring ownership (via
Pass() and friends)

+  virtual ~DTLSIdentityService();
+
+  // Request a DTLS identity. A new one will be gernerated if not existent.
+  // |identity_name| is used to identity an identity within an origin.

[Ryan Sleevi, 2013/06/06 23:57:37]

s/identity an identity/identify an identity/

[jiayl, 2013/06/13 21:50:45]

Done.

+  // |common_name| is the common name used to generated the certificate.
+  virtual void RequestIdentity(const std::string& identity_name,

[Ryan Sleevi, 2013/06/06 23:57:37]

COMMENT: Please expand on what these mean within the comment.

What is a "DTLS identity", why would there be multiple identities, and what or
how is the common name significant.

A reader of this header should be able to discern the "right" way to use this
class from reading the comments, and these headers rely on too much hidden
understanding about how to 'request'.

[jiayl, 2013/06/13 21:50:45]

Done.

+                               const std::string& common_name);
+
+ private:
+  // RenderProcessObserver implementation.
+  virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  void OnIdentityReady(const std::string& certificate,
+                       const std::string& private_key);
+
+  // The origin of the PeerConnection which owns this DTLSIdentityService.
+  GURL origin_;
+  scoped_ptr<DTLSIdentityObserver> observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DTLSIdentityService);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_DTLS_IDENTITY_SERVICE_H_