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

content/renderer/media/webrtc_identity_service.cc

+// 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.
+
+#include "content/renderer/media/webrtc_identity_service.h"
+
+#include "content/common/media/webrtc_identity_messages.h"
+#include "content/public/renderer/render_thread.h"
+
+namespace content {
+
+WebRTCIdentityService::WebRTCIdentityService(const GURL& origin)
+    : origin_(origin), pending_observer_(NULL), pending_request_id_(0) {

[Ami GONE FROM CHROMIUM, 2013/06/27 20:05:18]

s/0/-1/ to match browser side?

[jiayl, 2013/06/27 21:08:37]

Browser side initial value removed.

+  RenderThread::Get()->AddObserver(this);
+}
+
+WebRTCIdentityService::~WebRTCIdentityService() {
+  RenderThread::Get()->RemoveObserver(this);
+  if (pending_observer_) {
+    RenderThread::Get()->Send(
+        new WebRTCIdentityMsg_CancelRequest(pending_request_id_));
+  }
+}
+
+bool WebRTCIdentityService::RequestIdentity(
+    const std::string& identity_name,
+    const std::string& common_name,
+    webrtc::DTLSIdentityRequestObserver* observer) {
+  static int s_next_request_id = 0;

[Ami GONE FROM CHROMIUM, 2013/06/27 20:05:18]

This is not thread-safe.  
You might want base::AtomicSequenceNumber.

[jiayl, 2013/06/27 21:08:37]

Done.

+  DCHECK(observer);
+  if (pending_observer_)
+    return false;
+
+  pending_observer_ = observer;
+  pending_request_id_ = s_next_request_id++;
+  RenderThread::Get()->Send(new WebRTCIdentityMsg_RequestIdentity(
+      pending_request_id_, origin_, identity_name, common_name));
+  return true;
+}
+
+bool WebRTCIdentityService::OnControlMessageReceived(
+    const IPC::Message& message) {
+  if (!pending_observer_)
+    return false;
+
+  int old_pending_request_id = pending_request_id_;
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(WebRTCIdentityService, message)
+    IPC_MESSAGE_HANDLER(WebRTCIdentityHostMsg_IdentityReady, OnIdentityReady)
+    IPC_MESSAGE_HANDLER(WebRTCIdentityHostMsg_RequestFailed, OnRequestFailed)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+
+  if (pending_request_id_ == old_pending_request_id)
+    handled = false;
+
+  return handled;
+}
+
+void WebRTCIdentityService::OnIdentityReady(int request_id,
+                                            const std::string& certificate,
+                                            const std::string& private_key) {
+  if (request_id != pending_request_id_)
+    return;
+  pending_observer_->OnSuccess(certificate, private_key);
+  pending_observer_ = NULL;
+  pending_request_id_ = 0;

[Ami GONE FROM CHROMIUM, 2013/06/27 20:05:18]

ditto s/0/-1/

+}
+
+void WebRTCIdentityService::OnRequestFailed(int request_id, int error) {
+  if (request_id != pending_request_id_)
+    return;
+  pending_observer_->OnFailure(error);
+  pending_observer_ = NULL;
+  pending_request_id_ = 0;

[Ami GONE FROM CHROMIUM, 2013/06/27 20:05:18]

ditto s/0/-1/

+}
+
+}  // namespace content