Web Inspector: Update ESLint rules and run it over most of UserInterface

[Joseph Pecoraro]

Summary:
Update ESLint rules and run it over most of UserInterface

I ran it over everything except the Views folder, which is a beast on its own.
Updated the settings which catch reasonable issues.
There were some actual issues caught by this, but this update is only mostly pedantic changes.

[Joseph Pecoraro]

Created attachment 287847 [details]
[PATCH] Proposed Fix

[BJ Burg]

Comment on attachment 287847 [details]
[PATCH] Proposed Fix

View in context: https://bugs.webkit.org/attachment.cgi?id=287847&action=review

r=me

> Source/WebInspectorUI/UserInterface/Base/Object.js:41
> +            return listener;

Why not return null or throw an exception in the exceptional cases? These are almost always programming errors we want to fail hard on.

> Source/WebInspectorUI/UserInterface/Controllers/TimelineManager.js:992
> +        let nextRecord = function(list) { return list.shift() || null; };

This could be an arrow, I suppose.

[Joseph Pecoraro]

Comment on attachment 287847 [details]
[PATCH] Proposed Fix

View in context: https://bugs.webkit.org/attachment.cgi?id=287847&action=review

>> Source/WebInspectorUI/UserInterface/Base/Object.js:41
>> +            return listener;
> 
> Why not return null or throw an exception in the exceptional cases? These are almost always programming errors we want to fail hard on.

Okay

[Joseph Pecoraro]

<https://trac.webkit.org/changeset/205424>