Pass camera facing to WebKit

content/browser/renderer_host/media/media_devices_manager.cc

Index: content/browser/renderer_host/media/media_devices_manager.cc
diff --git a/content/browser/renderer_host/media/media_devices_manager.cc b/content/browser/renderer_host/media/media_devices_manager.cc
index ccc3b4d4e2ea3f5bbf0e3f6a0865f14bf1f71bf8..e8d7f7de3f06b7cc7a147ad292cf6559be1c0072 100644
--- a/content/browser/renderer_host/media/media_devices_manager.cc
+++ b/content/browser/renderer_host/media/media_devices_manager.cc
@@ -385,8 +385,7 @@ void MediaDevicesManager::VideoInputDevicesEnumerated(
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   MediaDeviceInfoArray snapshot;
   for (const auto& descriptor : descriptors) {
-    snapshot.emplace_back(descriptor.device_id, descriptor.GetNameAndModel(),
-                          std::string());
+    snapshot.emplace_back(descriptor);

[miu, 2017/01/05 21:55:33]

nit: push_back() would be more appropriate here.

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

Why? If using push_back(), I will need to create a temporary MediaDeviceInfo
object and incur one extra copy.

[miu, 2017/01/10 22:14:23]

push_back() takes a const-ref argument (or an rvalue). You are giving it a
const-ref type. std::vector will copy-construct in-place. There is no extra
copy. ;-)

emplace_back() takes arguments to a constructor of the class. So, C++ will take
your const-ref and invoke the copy-constructor in-place. Same thing as
push_back, but the compiler may have to do more work to parse/analyze the
varargs and choose a constructor.

http://en.cppreference.com/w/cpp/container/vector/emplace_back
http://en.cppreference.com/w/cpp/container/vector/push_back

Like I said, a nit point, but since your intention is to insert a copy of an
existing object (as opposed to constructing a different object and inserting
it), push_back() is slightly more appropriate.

[shenghao, 2017/01/11 12:00:53]

Actually, |snapshot| is a vector of MediaDeviceInfo and |descriptor| is a
VideoCaptureDeviceDescriptor, so I am creating the MediaDeviceInfo object
through emplace_back(). ;)

[miu, 2017/01/11 21:08:44]

OIC! Okay then, sounds good to me. :)

   }

[mcasas, 2017/01/05 20:26:37]

No {} for one-line bodies.

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

Done.

   DevicesEnumerated(MEDIA_DEVICE_TYPE_VIDEO_INPUT, snapshot);
 }