[truetype/GX] Clean up advance adjustment.

* src/truetype/ttgload.c (TT_Process_Simple_Glyph, load_truetype_glyph):
Move the advance adjustment from here...
* src/truetype/ttgxvar.c (TT_Vary_Apply_Glyph_Deltas): ... to here and
simplify arguments.
* src/truetype/ttgxvar.h (TT_Vary_Apply_Glyph_Deltas): Update prototype
with fewer arguments.
diff --git a/src/truetype/ttgload.c b/src/truetype/ttgload.c
index e2908d0..52f2136 100644
--- a/src/truetype/ttgload.c
+++ b/src/truetype/ttgload.c
@@ -985,24 +985,10 @@
         goto Exit;
 
       /* Deltas apply to the unscaled data. */
-      error = TT_Vary_Apply_Glyph_Deltas( loader->face,
-                                          loader->glyph_index,
+      error = TT_Vary_Apply_Glyph_Deltas( loader,
                                           outline,
                                           unrounded,
                                           (FT_UInt)n_points );
-
-      /* recalculate linear horizontal and vertical advances */
-      /* if we don't have HVAR and VVAR, respectively        */
-
-      /* XXX: change all FreeType modules to store `linear' and `vadvance' */
-      /*      in 26.6 format before the `base' module scales them to 16.16 */
-      if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
-        loader->linear = FT_PIX_ROUND( unrounded[n_points - 3].x -
-                                       unrounded[n_points - 4].x ) / 64;
-      if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
-        loader->vadvance = FT_PIX_ROUND( unrounded[n_points - 1].x -
-                                         unrounded[n_points - 2].x ) / 64;
-
       if ( error )
         goto Exit;
     }
@@ -1786,8 +1772,7 @@
         outline.contours   = contours;
 
         /* this must be done before scaling */
-        error = TT_Vary_Apply_Glyph_Deltas( loader->face,
-                                            glyph_index,
+        error = TT_Vary_Apply_Glyph_Deltas( loader,
                                             &outline,
                                             unrounded,
                                             (FT_UInt)outline.n_points );
@@ -1803,15 +1788,6 @@
         loader->pp3.y = points[2].y;
         loader->pp4.x = points[3].x;
         loader->pp4.y = points[3].y;
-
-        /* recalculate linear horizontal and vertical advances */
-        /* if we don't have HVAR and VVAR, respectively        */
-        if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
-          loader->linear = FT_PIX_ROUND( unrounded[1].x -
-                                         unrounded[0].x ) / 64;
-        if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
-          loader->vadvance = FT_PIX_ROUND( unrounded[3].x -
-                                           unrounded[2].x ) / 64;
       }
 
 #endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
@@ -2015,8 +1991,7 @@
         /* this call provides additional offsets */
         /* for each component's translation      */
         if ( FT_SET_ERROR( TT_Vary_Apply_Glyph_Deltas(
-                             face,
-                             glyph_index,
+                             loader,
                              &outline,
                              unrounded,
                              (FT_UInt)outline.n_points ) ) )
diff --git a/src/truetype/ttgxvar.c b/src/truetype/ttgxvar.c
index 36f70c8..232bdb4 100644
--- a/src/truetype/ttgxvar.c
+++ b/src/truetype/ttgxvar.c
@@ -3827,39 +3827,37 @@
    * @Description:
    *   Apply the appropriate deltas to the current glyph.
    *
-   * @Input:
-   *   face ::
-   *     A handle to the target face object.
-   *
-   *   glyph_index ::
-   *     The index of the glyph being modified.
-   *
-   *   n_points ::
-   *     The number of the points in the glyph, including
-   *     phantom points.
-   *
    * @InOut:
+   *   loader ::
+   *     A handle to the loader object.
+   *
    *   outline ::
-   *     The outline to change.
+   *     The outline to change, with appended phantom points.
    *
    * @Output:
    *   unrounded ::
    *     An array with `n_points' elements that is filled with unrounded
    *     point coordinates (in 26.6 format).
    *
+   * @Input
+   *   n_points ::
+   *     The number of the points in the glyph, including
+   *     phantom points.
+   *
    * @Return:
    *   FreeType error code.  0 means success.
    */
   FT_LOCAL_DEF( FT_Error )
-  TT_Vary_Apply_Glyph_Deltas( TT_Face      face,
-                              FT_UInt      glyph_index,
+  TT_Vary_Apply_Glyph_Deltas( TT_Loader    loader,
                               FT_Outline*  outline,
                               FT_Vector*   unrounded,
                               FT_UInt      n_points )
   {
     FT_Error   error;
+    TT_Face    face = loader->face;
     FT_Stream  stream = face->root.stream;
     FT_Memory  memory = stream->memory;
+    FT_UInt    glyph_index = loader->glyph_index;
 
     FT_Vector*  points_org = NULL;  /* coordinates in 16.16 format */
     FT_Vector*  points_out = NULL;  /* coordinates in 16.16 format */
@@ -4255,6 +4253,15 @@
       outline->points[i].y += FT_fixedToInt( point_deltas_y[i] );
     }
 
+    /* recalculate linear horizontal and vertical advances */
+    /* if we don't have HVAR and VVAR, respectively        */
+    if ( !( face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
+      loader->linear   = FT_PIX_ROUND( unrounded[n_points - 3].x -
+                                       unrounded[n_points - 4].x ) / 64;
+    if ( !( face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
+      loader->vadvance = FT_PIX_ROUND( unrounded[n_points - 1].x -
+                                       unrounded[n_points - 2].x ) / 64;
+
   Fail3:
     FT_FREE( point_deltas_x );
     FT_FREE( point_deltas_y );
diff --git a/src/truetype/ttgxvar.h b/src/truetype/ttgxvar.h
index a79b0d2..b3db2fc 100644
--- a/src/truetype/ttgxvar.h
+++ b/src/truetype/ttgxvar.h
@@ -361,8 +361,7 @@
 
 
   FT_LOCAL( FT_Error )
-  TT_Vary_Apply_Glyph_Deltas( TT_Face      face,
-                              FT_UInt      glyph_index,
+  TT_Vary_Apply_Glyph_Deltas( TT_Loader    loader,
                               FT_Outline*  outline,
                               FT_Vector*   unrounded,
                               FT_UInt      n_points );