Report dev error at viewer channel timeout

[zhouyx]

Fixes #25923

Another approach I've been thinking of is to introduce an opt_errorType param to the #reportError() method. But that doesn't apply to the uncaught error that we ret hrow.

The code looks like

    return Services.timerFor(this.win)
      .timeoutPromise(20000, messagingPromise, 'initMessagingChannel')
      .catch(reason => {
        const error = getChannelError(
          /** @type {!Error|string|undefined} */ (reason)
        );
        reportError(error);
        throw error;
      });

Do you know why we want to re-throw the error after calling reportError() (From my test, either one should get the error sent to endpoint)

[dvoytenko]

This is, imho, too nuanced to spread from the log system. We already export isUserError there. Can we also expose something like stripUserError?

[zhouyx]

Sure. I agree a helper method would be helpful if there are future use cases. Are you thinking of something like

error.message = stripUserError(error.message)

Or something like

error = convertToDevError(error)

[zhouyx]

Friendly ping : )