don't fail hard when getImageData is not allowed

src/chromeBadge.ts

@@ -150,11 +150,16 @@ export class ChromeBadge implements Badge {
 
     // Allow running outside the extension for testing
     if (window["chrome"] && window.chrome["browserAction"]) {
+      try {
         let imageData = this.ctx.getImageData(0,
                                               0,
                                               this.canvas.width,
                                               this.canvas.height);
         chrome.browserAction.setIcon({imageData});
+      } catch (e) {
+        // Might fail if browser has over-eager canvas fingerprinting countermeasures.
+        // There's nothing we can do then ...
+      }
     }
   }