Further optimize canvas read-backs

GitOrigin-RevId: 1c0227612db8f72d34f0c5198d749ba46d13b650

Author: ibesora

src/data/usvg/usvg_pb_renderer.ts

@@ -81,7 +81,7 @@ export function renderIcon(icon: Icon, options: RasterizationOptions): ImageData
 
     if (canvas === null) {
         canvas = getCanvas(10, 10);
-        context = canvas.getContext('2d') as Context;
+        context = canvas.getContext('2d', {willReadFrequently: true}) as Context;
     }
 
     canvas.width = renderedWidth;

test/integration/render-tests/elevated-line-pattern/int-zoom-constant-width/expected.png

@@ -2,7 +2,7 @@
   "version": 8,
   "metadata": {
     "test": {
-      "allowed": 0.00044,
+      "allowed": 0.00049,
       "pixelRatio": 2,
       "height": 64,
       "width": 64