🐛✅Fix tickevent tests for Safari (ampproject#21096)

* Fix tickevent tests for Safari

Fixes ampproject#21062

* Add comment to allow legit usage of console.warn

* ESLint fix

* Use dev() log instead of console

* Add import statement

* Fix lint

src/service/performance-impl.js

@@ -15,6 +15,7 @@
  */
 
 import {Services} from '../services';
+import {dev} from '../log';
 import {dict, map} from '../utils/object';
 import {getMode} from '../mode';
 import {getService, registerServiceBuilder} from '../service';
@@ -281,7 +282,15 @@ export class Performance {
       list.getEntries().forEach(processEntry);
       this.flush();
     });
-    observer.observe({entryTypes: entryTypesToObserve});
+
+    // Wrap observer.observe() in a try statement for testing, because
+    // Webkit throws an error if the entry types to observe are not natively
+    // supported.
+    try {
+      observer.observe({entryTypes: entryTypesToObserve});
+    } catch (err) {
+      dev()/*OK*/.warn(err);
+    }
   }
 
   /**

test/unit/test-performance.js

@@ -718,9 +718,7 @@ describes.realWin('PeformanceObserver metrics', {amp: true}, env => {
   }
 
   describe('should forward paint metrics for performance entries', () => {
-    // TODO(ericandrewlewis, 20721): Fails on Safari.
-    it.configure().skipSafari('created before performance service ' +
-        'registered', () => {
+    it('created before performance service registered', () => {
       // Pretend that the PaintTiming API exists.
       env.win.PerformancePaintTiming = true;
 
@@ -813,9 +811,7 @@ describes.realWin('PeformanceObserver metrics', {amp: true}, env => {
   });
 
   describe('should forward first input metrics for performance entries', () => {
-    // TODO(ericandrewlewis, 20721): Fails on Safari.
-    it.configure().skipSafari('created before performance service ' +
-        'registered', () => {
+    it('created before performance service registered', () => {
       // Pretend that the EventTiming API exists.
       env.win.PerformanceEventTiming = true;