Fix error handling now that canvas supports svgs

lib/spriteBackgroundImages.js

@@ -11,14 +11,7 @@ function getProperties(container, propertyName) {
 async function getCanvasImageFromImageAsset(imageAsset) {
   const canvasImage = new Image();
   await new Promise((resolve, reject) => {
-    canvasImage.onerror = err => {
-      if (err.message.includes('node-canvas was built without SVG support')) {
-        err.message = 'Adding SVG images to a sprite is not possible';
-      }
-
-      err.message += ` (${imageAsset.urlOrDescription})`;
-      reject(err);
-    };
+    canvasImage.onerror = err => reject(err);
     canvasImage.onload = resolve;
     canvasImage.src = imageAsset.rawSrc;
   });
@@ -27,7 +20,19 @@ async function getCanvasImageFromImageAsset(imageAsset) {
 
 async function getImageAssetFromCanvas(canvas, assetType, assetGraph) {
   if (assetType === 'Png') {
-    const rawSrc = await promisify(cb => canvas.toBuffer(cb))();
+    let rawSrc;
+    try {
+      rawSrc = await promisify(cb => canvas.toBuffer(cb))();
+    } catch (err) {
+      if (
+        err.message.includes(
+          'the surface type is not appropriate for the operation'
+        )
+      ) {
+        err.message += ' (are you trying to add an SVG to a sprite?)';
+      }
+      throw err;
+    }
     return {
       type: 'Png',
       rawSrc

test/spriteBackgroundImages.js

@@ -530,7 +530,7 @@ describe('spriteBackgroundImages', () => {
     await expect(
       assetGraph.queue(spriteBackgroundImages()),
       'to be rejected with',
-      /Adding SVG images to a sprite is not possible/
+      /are you trying to add an SVG to a sprite/
     );
   });
 });