libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_svc_layercontext.h

 /*
  *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 32 matching lines @@
 } LAYER_CONTEXT;
 
 typedef struct {
   int spatial_layer_id;
   int temporal_layer_id;
   int number_spatial_layers;
   int number_temporal_layers;
 
   int spatial_layer_to_encode;
 
+  // Workaround for multiple frame contexts
+  enum {
+    ENCODED = 0,
+    ENCODING,
+    NEED_TO_ENCODE
+  }encode_empty_frame_state;
+  struct lookahead_entry empty_frame;
+  int empty_frame_width;
+  int empty_frame_height;
+
   // Store scaled source frames to be used for temporal filter to generate
   // a alt ref frame.
   YV12_BUFFER_CONFIG scaled_frames[MAX_LAG_BUFFERS];
 
   // Layer context used for rate control in one pass temporal CBR mode or
   // two pass spatial mode. Defined for temporal or spatial layers for now.
   // Does not support temporal combined with spatial RC.
   LAYER_CONTEXT layer_context[MAX(VPX_TS_MAX_LAYERS, VPX_SS_MAX_LAYERS)];
 } SVC;
 
@@ skipping 36 matching lines @@
                                               int drain);
 
 // Start a frame and initialize svc parameters
 int vp9_svc_start_frame(struct VP9_COMP *const cpi);
 
 #ifdef __cplusplus
 }  // extern "C"
 #endif
 
 #endif  // VP9_ENCODER_VP9_SVC_LAYERCONTEXT_