Add mojo-based support for media device-change notifications.

content/renderer/media/media_devices_listener_impl.cc

Index: content/renderer/media/media_devices_listener_impl.cc
diff --git a/content/renderer/media/media_devices_listener_impl.cc b/content/renderer/media/media_devices_listener_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..858803645cc4068f3359ea89f11b549933f4d340
--- /dev/null
+++ b/content/renderer/media/media_devices_listener_impl.cc
@@ -0,0 +1,43 @@
+// Copyright 2016 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/media_devices_listener_impl.h"
+
+#include <utility>
+
+#include "base/memory/ptr_util.h"
+#include "content/public/renderer/render_frame.h"
+#include "content/renderer/media/media_devices_event_dispatcher.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+namespace content {
+
+// static
+void MediaDevicesListenerImpl::Create(
+    int render_frame_id,
+    ::mojom::MediaDevicesListenerRequest request) {
+  mojo::MakeStrongBinding(
+      base::MakeUnique<MediaDevicesListenerImpl>(render_frame_id),
+      std::move(request));
+}
+
+MediaDevicesListenerImpl::MediaDevicesListenerImpl(int render_frame_id)
+    : render_frame_id_(render_frame_id) {}
+
+MediaDevicesListenerImpl::~MediaDevicesListenerImpl() = default;
+
+void MediaDevicesListenerImpl::OnDevicesChanged(
+    MediaDeviceType type,
+    uint32_t subscription_id,
+    const MediaDeviceInfoArray& device_infos) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  base::WeakPtr<MediaDevicesEventDispatcher> event_dispatcher =
+      MediaDevicesEventDispatcher::GetForRenderFrame(
+          RenderFrame::FromRoutingID(render_frame_id_));
+  if (event_dispatcher)
+    event_dispatcher->DispatchDevicesChangedEvent(type, device_infos);
+}
+
+}  // namespace content