[util] Simplify shape-consumer by removing buffer arg

util/hb-ot-shape-closure.cc

@@ -48,13 +48,12 @@ struct shape_closure_consumer_t
 		       this);
   }
 
-  void init (hb_buffer_t  *buffer_,
-	     const font_options_t *font_opts)
+  void init (const font_options_t *font_opts)
   {
     glyphs = hb_set_create ();
     font = hb_font_reference (font_opts->get_font ());
     failed = false;
-    buffer = hb_buffer_reference (buffer_);
+    buffer = hb_buffer_create ();
   }
   void consume_line (const char   *text,
 		     unsigned int  text_len,

util/hb-subset.cc

@@ -42,8 +42,7 @@ struct subset_consumer_t
     subset_options.add_options (parser);
   }
 
-  void init (hb_buffer_t  *buffer_,
-	     const font_options_t *font_opts)
+  void init (const font_options_t *font_opts)
   {
     face = hb_face_reference (hb_font_get_face (font_opts->get_font ()));
     input = hb_subset_input_reference (subset_options.get_input ());

util/main-font-text.hh

@@ -78,9 +78,7 @@ struct main_font_text_t
     if (!input.text && !input.text_file)
       input.text_file = g_strdup ("-");
 
-    hb_buffer_t *buffer = hb_buffer_create ();
-    consumer.init (buffer, &font_opts);
-    hb_buffer_destroy (buffer);
+    consumer.init (&font_opts);
 
     unsigned int text_len;
     const char *text;

util/shape-consumer.hh

@@ -40,12 +40,11 @@ struct shape_consumer_t
     output.add_options (parser);
   }
 
-  void init (hb_buffer_t  *buffer_,
-	     const font_options_t *font_opts)
+  void init (const font_options_t *font_opts)
   {
     font = hb_font_reference (font_opts->get_font ());
     failed = false;
-    buffer = hb_buffer_reference (buffer_);
+    buffer = hb_buffer_create ();
 
     output.init (buffer, font_opts);
   }