Pass camera facing to WebKit

content/browser/renderer_host/media/media_stream_manager.cc

Index: content/browser/renderer_host/media/media_stream_manager.cc
diff --git a/content/browser/renderer_host/media/media_stream_manager.cc b/content/browser/renderer_host/media/media_stream_manager.cc
index 029b0638c4e3ced5da47532ccb1c32e5b6504b51..2581785c3ae957ee7631ce23a7a626402379a356 100644
--- a/content/browser/renderer_host/media/media_stream_manager.cc
+++ b/content/browser/renderer_host/media/media_stream_manager.cc
@@ -49,6 +49,7 @@
 #include "media/base/audio_parameters.h"
 #include "media/base/channel_layout.h"
 #include "media/base/media_switches.h"
+#include "media/capture/video/linux/camera_facing_chromeos.h"

[jochen (gone - plz use gerrit), 2017/01/05 12:17:59]

we shouldn't unconditionally include platform specific headers

[shenghao, 2017/01/06 09:43:01]

Done.

 #include "media/capture/video/video_capture_device_factory.h"
 #include "url/gurl.h"
 #include "url/origin.h"
@@ -67,6 +68,10 @@ base::LazyInstance<base::ThreadLocalPointer<MediaStreamManager>>::Leaky
     g_media_stream_manager_tls_ptr = LAZY_INSTANCE_INITIALIZER;
 
 namespace {
+
+base::LazyInstance<media::CameraFacingChromeOS>::Leaky g_camera_facing_ =

[jochen (gone - plz use gerrit), 2017/01/05 12:17:59]

why is that a singleton can't we create a new instance when we need one?

also, platform specific code should either go into platform specific files, or
needs to be #ifdef'd

[shenghao, 2017/01/06 09:43:01]

It's a lazy instance so it only be constructed when first used. We don't want to
create one instance for each use because constructing CameraFacingChromeOS
involving reading some data from file, which is slow.
done

+    LAZY_INSTANCE_INITIALIZER;
+
 // Creates a random label used to identify requests.
 std::string RandomLabel() {
   // An earlier PeerConnection spec [1] defined MediaStream::label alphabet as
@@ -207,12 +212,25 @@ MediaDeviceType ConvertToMediaDeviceType(MediaStreamType stream_type) {
   return NUM_MEDIA_DEVICE_TYPES;
 }
 
+VideoFacingMode GetVideoFacing(std::string device_id, std::string model_id) {
+  media::CameraFacingChromeOS::LensFacing facing =
+      g_camera_facing_.Get().GetCameraFacing(device_id, model_id);
+  switch (facing) {
+    case media::CameraFacingChromeOS::LensFacing::FRONT:
+      return VideoFacingMode::MEDIA_VIDEO_FACING_USER;
+    case media::CameraFacingChromeOS::LensFacing::BACK:
+      return VideoFacingMode::MEDIA_VIDEO_FACING_ENVIRONMENT;
+  }
+  return VideoFacingMode::MEDIA_VIDEO_FACING_NONE;
+}
+
 MediaStreamDevices ConvertToMediaStreamDevices(
     MediaStreamType stream_type,
     const MediaDeviceInfoArray& device_infos) {
   MediaStreamDevices devices;
   for (const auto& info : device_infos) {
-    devices.emplace_back(stream_type, info.device_id, info.label);
+    devices.emplace_back(stream_type, info.device_id, info.label,
+                         GetVideoFacing(info.device_id, info.model_id));
   }
 
   return devices;