Enable inter-layer prediction by default in test apps.

This sets the default inter-layer prediction mode in the test
applications equal to the default value used by WebRTC sender:
- 2 (enabled only for key frames) for normal video.
- 0 (enabled for all frames) for screen sharing.

Bug: none
Change-Id: I1b60d3b906838d2c6f1bef3bb7f7d881bb43534e
Reviewed-on: https://webrtc-review.googlesource.com/78620
Reviewed-by: Michael Horowitz <mhoro@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23446}

video/screenshare_loopback.cc

@@ -158,7 +158,7 @@ int NumSpatialLayers() {
 }
 
 DEFINE_int(inter_layer_pred,
-           1,
+           0,
            "Inter-layer prediction mode. "
            "0 - enabled, 1 - disabled, 2 - enabled only for key pictures.");
 InterLayerPredMode InterLayerPred() {

video/sv_loopback.cc

@@ -92,7 +92,7 @@ int VideoNumSpatialLayers() {
 }
 
 DEFINE_int(vinter_layer_pred,
-           1,
+           2,
            "Video inter-layer prediction mode. "
            "0 - enabled, 1 - disabled, 2 - enabled only for key pictures.");
 InterLayerPredMode VideoInterLayerPred() {
@@ -215,7 +215,7 @@ int ScreenshareNumSpatialLayers() {
 }
 
 DEFINE_int(sinter_layer_pred,
-           1,
+           0,
            "Screenshare inter-layer prediction mode. "
            "0 - enabled, 1 - disabled, 2 - enabled only for key pictures.");
 InterLayerPredMode ScreenshareInterLayerPred() {

video/video_loopback.cc

@@ -73,7 +73,7 @@ int NumTemporalLayers() {
 }
 
 DEFINE_int(inter_layer_pred,
-           1,
+           2,
            "Inter-layer prediction mode. "
            "0 - enabled, 1 - disabled, 2 - enabled only for key pictures.");
 InterLayerPredMode InterLayerPred() {