Begin adding support for tab mirroring via the MediaStream audio/video capturing

content/renderer/media/media_stream_dispatcher.cc

Index: content/renderer/media/media_stream_dispatcher.cc
diff --git a/content/renderer/media/media_stream_dispatcher.cc b/content/renderer/media/media_stream_dispatcher.cc
index 5d97ca0135a04ff79a8b149e1662bca9321c0b68..866d68c504229a4f10c7f6994160d2745ddfc673 100644
--- a/content/renderer/media/media_stream_dispatcher.cc
+++ b/content/renderer/media/media_stream_dispatcher.cc
@@ -117,26 +117,23 @@ void MediaStreamDispatcher::EnumerateDevices(
     media_stream::MediaStreamType type,
     const GURL& security_origin) {
   DCHECK(main_loop_->BelongsToCurrentThread());
-  DCHECK(type == content::MEDIA_STREAM_DEVICE_TYPE_AUDIO_CAPTURE ||
-         type == content::MEDIA_STREAM_DEVICE_TYPE_VIDEO_CAPTURE);
+  DCHECK_LT(content::MEDIA_NO_SERVICE, type);
+  DCHECK_GT(content::NUM_MEDIA_TYPES, type);
   DVLOG(1) << "MediaStreamDispatcher::EnumerateDevices("
            << request_id << ")";
 
-  EnumerationState* state =
-      (type == content::MEDIA_STREAM_DEVICE_TYPE_AUDIO_CAPTURE ?
-       &audio_enumeration_state_ : &video_enumeration_state_);
-  state->requests.push_back(
-      EnumerationRequest(event_handler, request_id));
+  EnumerationState& state = enumeration_state_[type];
+  state.requests.push_back(EnumerationRequest(event_handler, request_id));
 
-  if (state->cached_devices.get()) {
+  if (state.cached_devices.get()) {
     event_handler->OnDevicesEnumerated(
-        request_id, state->cached_devices->devices);
-  } else if (state->ipc_id < 0) {
+        request_id, state.cached_devices->devices);
+  } else if (state.ipc_id < 0) {
     Send(new MediaStreamHostMsg_EnumerateDevices(routing_id(),
                                                  next_ipc_id_,
                                                  type,
                                                  security_origin));
-    state->ipc_id = next_ipc_id_++;
+    state.ipc_id = next_ipc_id_++;
   }
 }
 
@@ -148,10 +145,10 @@ void MediaStreamDispatcher::StopEnumerateDevices(
            << request_id << ")";
 
   // Remove the request.
-  RemoveEnumerationRequest(
-      request_id, event_handler, &audio_enumeration_state_);
-  RemoveEnumerationRequest(
-      request_id, event_handler, &video_enumeration_state_);
+  for (int i = content::MEDIA_NO_SERVICE + 1; i < content::NUM_MEDIA_TYPES;
+       ++i) {
+    RemoveEnumerationRequest(request_id, event_handler, &enumeration_state_[i]);
+  }
 }
 
 void MediaStreamDispatcher::RemoveEnumerationRequest(
@@ -309,12 +306,15 @@ void MediaStreamDispatcher::OnDevicesEnumerated(
   DCHECK(main_loop_->BelongsToCurrentThread());
   DCHECK_GE(request_id, 0);
 
-  EnumerationState* state;
-  if (request_id == audio_enumeration_state_.ipc_id) {
-    state = &audio_enumeration_state_;
-  } else if (request_id == video_enumeration_state_.ipc_id) {
-    state = &video_enumeration_state_;
-  } else {
+  EnumerationState* state = NULL;
+  for (int i = content::MEDIA_NO_SERVICE + 1; i < content::NUM_MEDIA_TYPES;
+       ++i) {
+    if (request_id == enumeration_state_[i].ipc_id) {
+      state = &enumeration_state_[i];
+      break;
+    }
+  }
+  if (state == NULL) {
     // This could happen when requester has stopped enumeration while some
     // enumerated response is on the way. Have to stop the |label| because
     // this might be the first enumerated device list is received. This also
@@ -365,11 +365,12 @@ void MediaStreamDispatcher::OnDeviceOpened(
     if (request.ipc_request == request_id) {
       Stream new_stream;
       new_stream.handler = request.handler;
-      if (device_info.stream_type ==
-              content::MEDIA_STREAM_DEVICE_TYPE_VIDEO_CAPTURE) {
+      if (content::IsAudioMediaType(device_info.stream_type)) {
+        new_stream.audio_array.push_back(device_info);
+      } else if (content::IsVideoMediaType(device_info.stream_type)) {
         new_stream.video_array.push_back(device_info);
       } else {
-        new_stream.audio_array.push_back(device_info);
+        NOTREACHED();
       }
       label_stream_map_[label] = new_stream;
       if (request.handler) {