[fix] Image EncodingError for SVG in Safari iOS 11

Fixes an EncodingError exception being thrown in Safari iOS 11 when
decoding an SVG URL. The exception prevents the onLoad handler from
being called.

Close #1063

packages/react-native-web/src/modules/ImageLoader/index.js

@@ -52,12 +52,14 @@ const ImageLoader = {
     image.onerror = onError;
     image.onload = e => {
       // avoid blocking the main thread
+      const onDecode = () => onLoad(e);
       if (typeof image.decode === 'function') {
-        image.decode().then(() => { onLoad(e) });
+        // Safari currently throws exceptions when decoding svgs.
+        // We want to catch that error and allow the load handler
+        // to be forwarded to the onLoad handler in this case
+        image.decode().then(onDecode, onDecode);
       } else {
-        setTimeout(() => {
-          onLoad(e);
-        }, 0);
+        setTimeout(onDecode, 0);
       }
     };
     image.src = uri;