[v4 beta-13] On cordova resume event, angular/src/util/util.js fails

[MarkChrisLevy]

Bug Report

Ionic Info
Run ionic info from a terminal/cmd prompt and paste the output below.

@ionic/angular 4.0.0-beta13

Describe the Bug
When using cordova browser, util/util.js proxyEvent fails when on resume event is fired.

util.js:10 Uncaught TypeError: Cannot read property 'detail' of undefined
    at Channel.<anonymous> (util.js:10)
    at Channel.fire (cordova.js:798)
    at HTMLDocument.<anonymous> (cordova.js:1508)

@manucorporat made changes to util.js, adding support for back button event and it is missing the check if event isn't undefined/null, which for some reasons is the case for on resume. So the fix is very simple:

export function proxyEvent<T>(emitter: EventEmitter<T>, el: EventTarget, eventName: string) {
 el.addEventListener(eventName, (ev) => {
  emitter.emit(ev ? (ev as any).detail as T : undefined);
  });
}	

Steps to Reproduce
Steps to reproduce the behavior:

1. Load the web app, which uses cordova browser
2. open another tab
3. go back to the tab with the web app - the error is thrown

Expected Behavior
No error obviously.

[ionitron-bot]

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