Rename contexts in MACROBLOCKD, MACROBLOCKD_PLANE

Match them with new names in CommonContexts (part of AV1_COMMON), to
ensure they explicitly name the type of context they are referring to.

Rename the relevant function too for clarity.

BUG=aomedia:2610

Change-Id: I9de0d0dcd61bea5fe3916a1ae7763ea9d26675f4
diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index 4541008..0dc539f 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -341,7 +341,7 @@
   }
 
   set_plane_n4(xd, bw, bh, num_planes);
-  set_skip_context(xd, mi_row, mi_col, num_planes);
+  set_entropy_context(xd, mi_row, mi_col, num_planes);
 
   // Distance of Mb to the various image edges. These are specified to 8th pel
   // as they are always compared to values that are in 1/8th pel units
@@ -1465,7 +1465,7 @@
       }
     }
   }
-  if (mbmi->skip) av1_reset_skip_context(xd, bsize, num_planes);
+  if (mbmi->skip) av1_reset_entropy_context(xd, bsize, num_planes);
 
   decode_token_recon_block(pbi, td, r, bsize);
 }
diff --git a/av1/decoder/decodetxb.c b/av1/decoder/decodetxb.c
index 24c6031..541f4c9 100644
--- a/av1/decoder/decodetxb.c
+++ b/av1/decoder/decodetxb.c
@@ -337,11 +337,12 @@
       get_plane_block_size(bsize, pd->subsampling_x, pd->subsampling_y);
 
   TXB_CTX txb_ctx;
-  get_txb_ctx(plane_bsize, tx_size, plane, pd->above_context + col,
-              pd->left_context + row, &txb_ctx);
+  get_txb_ctx(plane_bsize, tx_size, plane, pd->above_entropy_context + col,
+              pd->left_entropy_context + row, &txb_ctx);
   const uint8_t cul_level =
       av1_read_coeffs_txb(cm, xd, r, row, col, plane, &txb_ctx, tx_size);
-  av1_set_contexts(xd, pd, plane, plane_bsize, tx_size, cul_level, col, row);
+  av1_set_entropy_contexts(xd, pd, plane, plane_bsize, tx_size, cul_level, col,
+                           row);
 
   if (is_inter_block(mbmi)) {
     const PLANE_TYPE plane_type = get_plane_type(plane);