[unsafe-to-break] Mark all positions as unsafe in alternative shapers

src/hb-coretext.cc

@@ -1180,6 +1180,9 @@ resize_and_retry:
 	pos->x_advance = info->mask;
 	pos->x_offset = info->var1.i32;
 	pos->y_offset = info->var2.i32;
+
+	info->mask = HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
+
 	info++, pos++;
       }
     else
@@ -1188,6 +1191,9 @@ resize_and_retry:
 	pos->y_advance = info->mask;
 	pos->x_offset = info->var1.i32;
 	pos->y_offset = info->var2.i32;
+
+	info->mask = HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
+
 	info++, pos++;
       }
 

src/hb-directwrite.cc

@@ -880,6 +880,8 @@ retry_getglyphs:
     pos->x_offset =
       x_mult * (isRightToLeft ? -info->var1.i32 : info->var1.i32);
     pos->y_offset = y_mult * info->var2.i32;
+
+    info->mask = HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
   }
 
   if (isRightToLeft)

src/hb-graphite2.cc

@@ -355,6 +355,7 @@ _hb_graphite2_shape (hb_shape_plan_t    *shape_plan,
       hb_glyph_info_t *info = &buffer->info[clusters[i].base_glyph + j];
       info->codepoint = gids[clusters[i].base_glyph + j];
       info->cluster = clusters[i].cluster;
+      info->mask = HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
       info->var1.i32 = clusters[i].advance;     // all glyphs in the cluster get the same advance
     }
   }

src/hb-uniscribe.cc

@@ -1024,6 +1024,8 @@ retry:
     pos->x_advance = x_mult * (int32_t) info->mask;
     pos->x_offset = x_mult * (backward ? -info->var1.i32 : info->var1.i32);
     pos->y_offset = y_mult * info->var2.i32;
+
+    info->mask = HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
   }
 
   if (backward)