One month in Blink

On October 1, I began working in Opera’s new Web Technology team, tasked with improving the Web platform by contributing to the Chromium and Blink projects. Most of my effort has been on the Blink side, and it has been a very pleasant experience so far. Since I’ve worked so much with <video> before, I jumped right into that area and looked for things to work on. Chromium/Blink is a big code base which will take time to get intimately familiar with, but I was still able to make small improvements in a few areas.

Event handler attributes

My colleague Henrik reported that onplay and friends were missing on HTMLMediaElement, and I thought it surely would be easy to fix. However, I am easily distracted, so instead of just adding them I decided to implement GlobalEventHandlers and WindowEventHandlers, which ended up taking me 11 commits and even requiring IDL code generator (Perl!) changes. Now onplay is supported, but you probably don’t want to use it – use addEventListener('play', func) if uncertain!

While in the neighborhood, I also made the onerror attribute on <body> and <frameset> work per spec. I was a bit surprised to find this broken, presumably it isn’t that important for site compat...

Removing features

Although I’m quite happy with Blink code, I was surprised to find how much non-standard stuff there is, including prefixed APIs, undocumented quirks and things that have been removed from the spec. Fortunately, the Blink project is supportive of removing these things, with care, and I’ve now picked most of the low-hanging fruit on HTMLMediaElement, getting rid of a weird quirk, webkitPreservesPitch, webkitHasClosedCaptions, webkitClosedCaptionsVisible, startTime and initialTime.

Counting features

When there’s a risk that removing a feature is going to break the Web, the first step is to figure out by how much. UseCounter counts (opt-in) which features are used on each page view, so I went ahead and added/improved counters for various things that would be nice to eventually remove: a bunch of prefixed HTMLMediaElement APIs, the TextTrackCue constructor, the beforeload event and the two (!) prefixed fullscreen APIs. There’s also the media attribute on <source>, which is still in the spec, but getting usage data will help us decide whether to remove it.

Fixing bugs

It’s a beautiful thing when you can fix a bug just by removing code, and I did so this month by removing the width and height properties from the <video> intrinsic size logic. After my fix intrinsic size is still not per spec, but at least it’s less wrong.

In my only non-trivial Chromium contribution, I made CookieMonster wait for disk flush when deleting cookies, so that cookies are really gone when the UI says they are. This involved fixing a flaky test, which was fun.

Loading text tracks

I began looking into <track> and WebVTT and soon stumbled upon a FIXME in TextTrackLoader, which is what feeds data to the WebVTT parser. Unable to resist the bait, I refactored TextTrackLoader to use RawResource and removed TextTrackResource. Finally, I fixed some other minor issues and fiddled a bit with the TextTrack IDL.

One year ago

Also this month, one year has passed since my final commit in Core (Presto), which was on October 12, 2012. I was a little bit sad when I noticed this anniversary, but at the same I’m really happy about working on Chromium and Blink. Hopefully the next month will be even better!

The Web Technology team (source)

One thought on “One month in Blink

  1. 😀 You make your job sound so interesting.

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