Sync changes from mozilla-central gfx/wr

webrender/res/ps_text_run.glsl

@@ -186,9 +186,11 @@ void main(void) {
 #else
     float raster_scale = float(ph.user_data.z) / 65535.0;
 
+    // Scale in which the glyph is snapped when rasterized.
+    float glyph_raster_scale = raster_scale * task.device_pixel_scale;
+
     // Scale from glyph space to local space.
-    float glyph_scale_inv = res.scale / (raster_scale * task.device_pixel_scale);
-    float glyph_scale = 1.0 / glyph_scale_inv;
+    float glyph_scale_inv = res.scale / glyph_raster_scale;
 
     // Glyph raster pixels do not include the impact of the transform. Instead it was
     // replaced with an identity transform during glyph rasterization. As such only the
@@ -204,7 +206,7 @@ void main(void) {
     // - The transform has perspective or does not have a 2d inverse (Screen or local space).
     // - The transform's scale will result in result in very large rasterized glyphs and
     //   we clamped the size. This will imply local raster space.
-    vec2 raster_glyph_offset = floor(glyph.offset * glyph_scale + snap_bias);
+    vec2 raster_glyph_offset = floor(glyph.offset * glyph_raster_scale + snap_bias) / res.scale;
 
     // Compute the glyph rect in local space.
     //

webrender/src/composite.rs

@@ -304,8 +304,7 @@ impl CompositeState {
     ) {
         let mut visible_tile_count = 0;
 
-        for key in &tile_cache.tiles_to_draw {
-            let tile = &tile_cache.tiles[key];
+        for tile in tile_cache.tiles.values() {
             if !tile.is_visible {
                 // This can occur when a tile is found to be occluded during frame building.
                 continue;
@@ -335,8 +334,8 @@ impl CompositeState {
             let tile_id = tile_cache.native_surface_id.map(|surface_id| {
                 NativeTileId {
                     surface_id,
-                    x: key.x,
-                    y: key.y,
+                    x: tile.tile_offset.x,
+                    y: tile.tile_offset.y,
                 }
             });