[face] Add hb_face_create_from_file_or_fail()

New API:
+ hb_face_create_from_file_or_fail()

docs/harfbuzz-sections.txt

@@ -358,6 +358,7 @@ hb_face_count
 hb_face_t
 hb_face_create
 hb_face_create_or_fail
+hb_face_create_from_file_or_fail
 hb_reference_table_func_t
 hb_face_create_for_tables
 hb_face_get_empty

src/hb-blob.cc

@@ -617,10 +617,9 @@ hb_blob_create_from_file (const char *file_name)
 
 /**
  * hb_blob_create_from_file_or_fail:
- * @file_name: A font filename
+ * @file_name: A filename
  *
- * Creates a new blob containing the data from the
- * specified binary font file.
+ * Creates a new blob containing the data from the specified file.
  *
  * The filename is passed directly to the system on all platforms,
  * except on Windows, where the filename is interpreted as UTF-8.

src/hb-face.cc

@@ -272,7 +272,7 @@ hb_face_create (hb_blob_t    *blob,
  * contains no usable font face at the specified index.
  *
  * Return value: (transfer full): The new face object, or `NULL` if
- * no face is found at the specified index
+ * no face is found at the specified index.
  *
  * XSince: REPLACEME
  **/
@@ -291,6 +291,33 @@ hb_face_create_or_fail (hb_blob_t    *blob,
   return face;
 }
 
+/**
+ * hb_face_create_from_file_or_fail:
+ * @file_name: A font filename
+ * @index: The index of the face within the file
+ *
+ * A thin wrapper around hb_blob_create_from_file_or_fail()
+ * followed by hb_face_create_or_fail().
+ *
+ * Return value: (transfer full): The new face object, or `NULL` if
+ * no face is found at the specified index or the file cannot be read.
+ *
+ * XSince: REPLACEME
+ **/
+HB_EXTERN hb_face_t *
+hb_face_create_from_file_or_fail (const char   *file_name,
+				  unsigned int  index)
+{
+  hb_blob_t *blob = hb_blob_create_from_file_or_fail (file_name);
+  if (unlikely (!blob))
+    return nullptr;
+
+  hb_face_t *face = hb_face_create_or_fail (blob, index);
+  hb_blob_destroy (blob);
+
+  return face;
+}
+
 /**
  * hb_face_get_empty:
  *

src/hb-face.h

@@ -63,6 +63,10 @@ HB_EXTERN hb_face_t *
 hb_face_create_or_fail (hb_blob_t    *blob,
 			unsigned int  index);
 
+HB_EXTERN hb_face_t *
+hb_face_create_from_file_or_fail (const char   *file_name,
+				  unsigned int  index);
+
 /**
  * hb_reference_table_func_t:
  * @face: an #hb_face_t to reference table for