Add support for device-change notifications to MediaStreamDispatcher and MediaStreamDispatcherHost

content/common/media/media_stream_messages.h

Index: content/common/media/media_stream_messages.h
diff --git a/content/common/media/media_stream_messages.h b/content/common/media/media_stream_messages.h
index 9a745a14b0369e423f0d16cbb7ac784285010c4d..d4847c214644679e3894dc00a2c978873920220c 100644
--- a/content/common/media/media_stream_messages.h
+++ b/content/common/media/media_stream_messages.h
@@ -95,6 +95,9 @@ IPC_MESSAGE_ROUTED3(MediaStreamMsg_DeviceOpened,
 IPC_MESSAGE_ROUTED1(MediaStreamMsg_DeviceOpenFailed,
                     int /* request id */)
 
+// The browser has detected a change in the set of media devices.
+IPC_MESSAGE_ROUTED0(MediaStreamMsg_DevicesChanged)
+
 // Messages sent from the renderer to the browser.
 
 // Request a new media stream.
@@ -140,3 +143,12 @@ IPC_MESSAGE_CONTROL5(MediaStreamHostMsg_OpenDevice,
 IPC_MESSAGE_CONTROL2(MediaStreamHostMsg_CloseDevice,
                      int /* render frame id */,
                      std::string /*label*/)
+
+// Subscribe to notifications about changes in the set of media devices.
+IPC_MESSAGE_CONTROL2(MediaStreamHostMsg_SubscribeToDeviceChangeNotifications,
+                     int /* render frame id */,
+                     url::Origin /* security origin */)
+
+// Cancel notifications about changes in the set of media devices.
+IPC_MESSAGE_CONTROL1(MediaStreamHostMsg_CancelDeviceChangeNotifications,
+                     int /* render frame id */)