Limit max spatial layer to be configured through field trial (3->2) to match current limit in VP9En…

webrtc/media/engine/webrtcvideoengine2.cc

Index: webrtc/media/engine/webrtcvideoengine2.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2.cc b/webrtc/media/engine/webrtcvideoengine2.cc
index cd05f8e6ff5bbe48c820639f10477c8e88dc3306..b977521f9eb4627341b85b070ad54c3a15521d9b 100644
--- a/webrtc/media/engine/webrtcvideoengine2.cc
+++ b/webrtc/media/engine/webrtcvideoengine2.cc
@@ -325,7 +325,7 @@ bool GetVp9LayersFromFieldTrialGroup(int* num_spatial_layers,
              num_temporal_layers) != 2) {
     return false;
   }
-  const int kMaxSpatialLayers = 3;
+  const int kMaxSpatialLayers = 2;
   if (*num_spatial_layers > kMaxSpatialLayers || *num_spatial_layers < 1)
     return false;