Use ImageBitmap.close when no longer needed.

This should free the underlying textures without waiting
for a GC to happen.

static/background-blur-worker.js

@@ -23,16 +23,20 @@ async function loadImageSegmenter() {
 loadImageSegmenter();
 
 onmessage = e => {
+    let bitmap = e.data.bitmap;
+    if(!(bitmap instanceof ImageBitmap)) {
+        postMessage(new Error('Bad type for worker data'));
+        return;
+    }
+
     if(!imageSegmenter) {
         // not ready yet
+        bitmap.close();
         postMessage(null);
         return;
     }
 
     try {
-        let bitmap = e.data.bitmap;
-        if(!(bitmap instanceof ImageBitmap))
-            throw new Error('Bad type for worker data');
         let width = bitmap.width;
         let height = bitmap.height;
         imageSegmenter.segmentForVideo(
@@ -52,6 +56,7 @@ onmessage = e => {
             },
         );
     } catch(e) {
+        bitmap.close();
         postMessage(e);
     }
 };

static/galene.js

@@ -1252,6 +1252,7 @@ let filters = {
         },
         draw: async function(src, ctx) {
             let bitmap = await createImageBitmap(src);
+            try {
                 let p = new Promise((resolve, reject) => {
                     this.userdata.worker.onmessage = e => {
                         if(e && e.data) {
@@ -1292,6 +1293,11 @@ let filters = {
                 ctx.filter = 'none';
                 ctx.drawImage(result.bitmap, 0, 0);
                 ctx.globalCompositeOperation = 'source-over';
+
+                mask.close();
+            } finally {
+                bitmap.close();
+            }
             return true;
         },
     },