clip: Use a smaller tile representation for mask images.

webrender/src/clip.rs

@@ -17,7 +17,7 @@ use gpu_types::{BoxShadowStretchMode};
 use image::{self, Repetition};
 use intern;
 use internal_types::FastHashSet;
-use prim_store::{ClipData, ImageMaskData, SpaceMapper, VisibleImageTile};
+use prim_store::{ClipData, ImageMaskData, SpaceMapper, VisibleMaskImageTile};
 use render_task::to_cache_size;
 use resource_cache::{ImageRequest, ResourceCache};
 use std::{cmp, u32};
@@ -316,12 +316,9 @@ impl ClipNode {
                                     data.write_gpu_blocks(request);
                                 }
 
-                                mask_tiles.push(VisibleImageTile {
+                                mask_tiles.push(VisibleMaskImageTile {
                                     tile_offset: tile.offset,
                                     handle,
-                                    edge_flags: tile.edge_flags,
-                                    local_rect: tile.rect,
-                                    local_clip_rect: visible_rect,
                                 });
                             }
                         }
@@ -821,7 +818,7 @@ impl ClipItemKey {
 pub enum ClipItem {
     Rectangle(LayoutRect, ClipMode),
     RoundedRectangle(LayoutRect, BorderRadius, ClipMode),
-    Image { mask: ImageMask, visible_tiles: Option<Vec<VisibleImageTile>> },
+    Image { mask: ImageMask, visible_tiles: Option<Vec<VisibleMaskImageTile>> },
     BoxShadow(BoxShadowClipSource),
 }
 

webrender/src/prim_store.rs

@@ -369,6 +369,14 @@ pub struct VisibleImageTile {
     pub local_clip_rect: LayoutRect,
 }
 
+#[derive(Debug)]
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+pub struct VisibleMaskImageTile {
+    pub tile_offset: TileOffset,
+    pub handle: GpuCacheHandle,
+}
+
 #[derive(Debug)]
 pub struct VisibleGradientTile {
     pub handle: GpuCacheHandle,