Correctly set iOS VideoToolbox encoder start bitrate.

The settings struct specifies bitrate in kbps, but we are
treating it as bps.

Bug: webrtc:9113
Change-Id: I27745da93aaec68041ea4283b45eccb35d820793
Reviewed-on: https://webrtc-review.googlesource.com/66960
Reviewed-by: Anders Carlsson <andersc@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22743}
diff --git a/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm b/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm
index a818c27..792dad5 100644
--- a/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm
+++ b/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm
@@ -330,7 +330,7 @@
   _mode = settings.mode;
 
   // We can only set average bitrate on the HW encoder.
-  _targetBitrateBps = settings.startBitrate;
+  _targetBitrateBps = settings.startBitrate * 1000;  // startBitrate is in kbps.
   _bitrateAdjuster->SetTargetBitrateBps(_targetBitrateBps);
 
   // TODO(tkchin): Try setting payload size via