[minor] Add unlikely() when checking for error

src/hb-face.cc

diff --git a/src/hb-face.cc b/src/hb-face.cc
index a15687c..900014f 100644
--- a/src/hb-face.cc
+++ b/src/hb-face.cc
@@ -756,7 +756,7 @@
   hb_face_builder_data_t *data = (hb_face_builder_data_t *) face->user_data;
 
   hb_face_builder_data_t::table_entry_t *entry = data->tables.push ();
-  if (data->tables.in_error())
+  if (unlikely (data->tables.in_error()))
     return false;
 
   entry->tag = tag;

src/hb-ot-glyf-table.hh

diff --git a/src/hb-ot-glyf-table.hh b/src/hb-ot-glyf-table.hh
index 5470bd9..ec77c2b 100644
--- a/src/hb-ot-glyf-table.hh
+++ b/src/hb-ot-glyf-table.hh
@@ -186,7 +186,7 @@
     | hb_map (&SubsetGlyph::padded_size)
     ;
 
-    if (c->serializer->in_error ()) return_trace (false);
+    if (unlikely (c->serializer->in_error ())) return_trace (false);
     return_trace (c->serializer->check_success (_add_loca_and_head (c->plan,
 								    padded_offsets)));
   }

src/hb-ot-layout-gsubgpos.hh

diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index 101d03e..82ef694 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -89,7 +89,7 @@
 
   bool is_lookup_done (unsigned int lookup_index)
   {
-    if (done_lookups->in_error ())
+    if (unlikely (done_lookups->in_error ()))
       return true;
 
     /* Have we visited this lookup with the current set of glyphs? */
@@ -162,10 +162,10 @@
 
   bool is_lookup_visited (unsigned lookup_index)
   {
-    if (lookup_count++ > HB_MAX_LOOKUP_INDICES)
+    if (unlikely (lookup_count++ > HB_MAX_LOOKUP_INDICES))
       return true;
 
-    if (visited_lookups->in_error ())
+    if (unlikely (visited_lookups->in_error ()))
       return true;
 
     return visited_lookups->has (lookup_index);
@@ -3397,7 +3397,7 @@
     hb_set_t alternate_feature_indices;
     if (version.to_int () >= 0x00010001u)
       (this+featureVars).closure_features (lookup_indices, &alternate_feature_indices);
-    if (alternate_feature_indices.in_error()) {
+    if (unlikely (alternate_feature_indices.in_error())) {
       feature_indices->successful = false;
       return;
     }