[subset] In subset fuzzer run through drop hints and keep hints pathways.

test/fuzzing/hb-subset-fuzzer.cc

@@ -12,10 +12,15 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
                                     HB_MEMORY_MODE_READONLY, NULL, NULL);
   hb_face_t *face = hb_face_create (blob, 0);
   hb_subset_profile_t *profile = hb_subset_profile_create ();
-  // TODO(grieger): Loop through common profiles (hints, no hints, etc.)
+
   hb_subset_input_t *input = hb_subset_input_create_or_fail ();
+  *hb_subset_input_drop_hints(input) = false;
   hb_set_t *codepoints = hb_subset_input_unicode_set (input);
 
+  hb_subset_input_t *input_drop_hints = hb_subset_input_create_or_fail ();
+  *hb_subset_input_drop_hints(input_drop_hints) = true;
+  hb_set_t *codepoints_drop_hints = hb_subset_input_unicode_set (input);
+
   const hb_codepoint_t text[] =
       {
         'A', 'B', 'C', 'D', 'E', 'X', 'Y', 'Z', '1', '2',
@@ -24,12 +29,17 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
   for (int i = 0; i < sizeof (text) / sizeof (hb_codepoint_t); i++)
   {
     hb_set_add (codepoints, text[i]);
+    hb_set_add (codepoints_drop_hints, text[i]);
   }
 
   hb_face_t *result = hb_subset (face, profile, input);
+  hb_face_destroy (result);
 
+  result = hb_subset (face, profile, input_drop_hints);
   hb_face_destroy (result);
+
   hb_subset_input_destroy (input);
+  hb_subset_input_destroy (input_drop_hints);
   hb_subset_profile_destroy (profile);
   hb_face_destroy (face);
   hb_blob_destroy (blob);