Category Archives: Chromium

End of the year Update: 2019 edition

Published / by mario / Leave a Comment

It’s the end of December and it seems that yet another year has gone by, so I figured that I’d write an EOY update to summarize my main work at Igalia as part of our Chromium team, as my humble attempt to make up for the lack of posts in this blog during this year.

I did quit a few things this year, but for the purpose of this blog post I’ll focus on what I consider the most relevant ones: work on the Servicification and the Blink Onion Soup projects, the migration to the new Mojo APIs and the BrowserInterfaceBroker, as well as a summary of the conferences I attended, both as a regular attendee and a speaker.

But enough of an introduction, let’s dive now into the gory details…

Servicification: migration to the Identity service

As explained in my previous post from January, I’ve started this year working on the Chromium Servicification (s13n) Project. More specifically, I joined my team mates in helping with the migration to the Identity service by updating consumers of several classes from the sign-in component to ensure they now use the new IdentityManager API instead of directly accessing those other lower level APIs.

This was important because at some point the Identity Service will run in a separate process, and a precondition for that to happen is that all access to sign-in related functionality would have to go through the IdentityManager, so that other process can communicate with it directly via Mojo interfaces exposed by the Identity service.

I’ve already talked long enough in my previous post, so please take a look in there if you want to know more details on what that work was exactly about.

The Blink Onion Soup project

Interestingly enough, a bit after finishing up working on the Identity service, our team dived deep into helping with another Chromium project that shared at least one of the goals of the s13n project: to improve the health of Chromium’s massive codebase. The project is code-named Blink Onion Soup and its main goal is, as described in the original design document from 2015, to “simplify the codebase, empower developers to implement features that run faster, and remove hurdles for developers interfacing with the rest of the Chromium”. There’s also a nice slide deck from 2016’s BlinkOn 6 that explains the idea in a more visual way, if you’re interested.


“Layers”, by Robert Couse-Baker (CC BY 2.0)

In a nutshell, the main idea is to simplify the codebase by removing/reducing the several layers of located between Chromium and Blink that were necessary back in the day, before Blink was forked out of WebKit, to support different embedders with their particular needs (e.g. Epiphany, Chromium, Safari…). Those layers made sense back then but these days Blink’s only embedder is Chromium’s content module, which is the module that Chrome and other Chromium-based browsers embed to leverage Chromium’s implementation of the Web Platform, and also where the multi-process and sandboxing architecture is implemented.

And in order to implement the multi-process model, the content module is split in two main parts running in separate processes, which communicate among each other over IPC mechanisms: //content/browser, which represents the “browser process” that you embed in your application via the Content API, and //content/renderer, which represents the “renderer process” that internally runs the web engine’s logic, that is, Blink.

With this in mind, the initial version of the Blink Onion Soup project (aka “Onion Soup 1.0”) project was born about 4 years ago and the folks spearheading this proposal started working on a 3-way plan to implement their vision, which can be summarized as follows:

  1. Migrate usage of Chromium’s legacy IPC to the new IPC mechanism called Mojo.
  2. Move as much functionality as possible from //content/renderer down into Blink itself.
  3. Slim down Blink’s public APIs by removing classes/enums unused outside of Blink.

Three clear steps, but definitely not easy ones as you can imagine. First of all, if we were to remove levels of indirection between //content/renderer and Blink as well as to slim down Blink’s public APIs as much as possible, a precondition for that would be to allow direct communication between the browser process and Blink itself, right?

In other words, if you need your browser process to communicate with Blink for some specific purpose (e.g. reacting in a visual way to a Push Notification), it would certainly be sub-optimal to have something like this:

…and yet that is what would happen if we kept using Chromium’s legacy IPC which, unlike Mojo, doesn’t allow us to communicate with Blink directly from //content/browser, meaning that we’d need to go first through //content/renderer and then navigate through different layers to move between there and Blink itself.

In contrast, using Mojo would allow us to have Blink implement those remote services internally and then publicly declare the relevant Mojo interfaces so that other processes can interact with them without going through extra layers. Thus, doing that kind of migration would ultimately allow us to end up with something like this:

…which looks nicer indeed, since now it is possible to communicate directly with Blink, where the remote service would be implemented (either in its core or in a module). Besides, it would no longer be necessary to consume Blink’s public API from //content/renderer, nor the other way around, enabling us to remove some code.

However, we can’t simply ignore some stuff that lives in //content/renderer implementing part of the original logic so, before we can get to the lovely simplification shown above, we would likely need to move some logic from //content/renderer right into Blink, which is what the second bullet point of the list above is about. Unfortunately, this is not always possible but, whenever it is an option, the job here would be to figure out what of that logic in //content/renderer is really needed and then figure out how to move it into Blink, likely removing some code along the way.

This particular step is what we commonly call “Onion Soup’ing //content/renderer/<feature>(not entirely sure “Onion Soup” is a verb in English, though…) and this is for instance how things looked before (left) and after (right) Onion Souping a feature I worked on myself: Chromium’s implementation of the Push API:


Onion Soup’ing //content/renderer/push_messaging

Note how the whole design got quite simplified moving from the left to the right side? Well, that’s because some abstract classes declared in Blink’s public API and implemented in //content/renderer (e.g. WebPushProvider, WebPushMessagingClient) are no longer needed now that those implementations got moved into Blink (i.e. PushProvider and PushMessagingClient), meaning that we can now finally remove them.

Of course, there were also cases where we found some public APIs in Blink that were not used anywhere, as well as cases where they were only being used inside of Blink itself, perhaps because nobody noticed when that happened at some point in the past due to some other refactoring. In those cases the task was easier, as we would just remove them from the public API, if completely unused, or move them into Blink if still needed there, so that they are no longer exposed to a content module that no longer cares about that.

Now, trying to provide a high-level overview of what our team “Onion Soup’ed” this year, I think I can say with confidence that we migrated (or helped migrate) more than 10 different modules like the one I mentioned above, such as android/, appcache/, media/stream/, media/webrtc, push_messaging/ and webdatabase/, among others. You can see the full list with all the modules migrated during the lifetime of this project in the spreadsheet tracking the Onion Soup efforts.

In my particular case, I “Onion Soup’ed” the PushMessagingWebDatabase and SurroundingText features, which was a fairly complete exercise as it involved working on all the 3 bullet points: migrating to Mojo, moving logic from //content/renderer to Blink and removing unused classes from Blink’s public API.

And as for slimming down Blink’s public API, I can tell that we helped get to a point where more than 125 classes/enums were removed from that Blink’s public APIs, simplifying and reducing the Chromium code- base along the way, as you can check in this other spreadsheet that tracked that particular piece of work.

But we’re not done yet! While overall progress for the Onion Soup 1.0 project is around 90% right now, there are still a few more modules that require “Onion Soup’ing”, among which we’ll be tackling media/ (already WIP) and accessibility/ (starting in 2020), so there’s quite some more work to be done on that regard.

Also, there is a newer design document for the so-called Onion Soup 2.0 project that contains some tasks that we have been already working on for a while, such as “Finish Onion Soup 1.0”, “Slim down Blink public APIs”, “Switch Mojo to new syntax” and “Convert legacy IPC in //content to Mojo”, so definitely not done yet. Good news here, though: some of those tasks are already quite advanced already, and in the particular case of the migration to the new Mojo syntax it’s nearly done by now, which is precisely what I’m talking about next…

Migration to the new Mojo APIs and the BrowserInterfaceBroker

Along with working on “Onion Soup’ing” some features, a big chunk of my time this year went also into this other task from the Onion Soup 2.0 project, where I was lucky enough again not to be alone, but accompanied by several of my team mates from Igalia‘s Chromium team.

This was a massive task where we worked hard to migrate all of Chromium’s codebase to the new Mojo APIs that were introduced a few months back, with the idea of getting Blink updated first and then having everything else migrated by the end of the year.


Progress of migrations to the new Mojo syntax: June 1st – Dec 23rd, 2019

But first things first: you might be wondering what was wrong with the “old” Mojo APIs since, after all, Mojo is the new thing we were migrating to from Chromium’s legacy API, right?

Well, as it turns out, the previous APIs had a few problems that were causing some confusion due to not providing the most intuitive type names (e.g. what is an InterfacePtrInfo anyway?), as well as being quite error-prone since the old types were not as strict as the new ones enforcing certain conditions that should not happen (e.g. trying to bind an already-bound endpoint shouldn’t be allowed). In the Mojo Bindings Conversion Cheatsheet you can find an exhaustive list of cases that needed to be considered, in case you want to know more details about these type of migrations.

Now, as a consequence of this additional complexity, the task wouldn’t be as simple as a “search & replace” operation because, while moving from old to new code, it would often be necessary to fix situations where the old code was working fine just because it was relying on some constraints not being checked. And if you top that up with the fact that there were, literally, thousands of lines in the Chromium codebase using the old types, then you’ll see why this was a massive task to take on.

Fortunately, after a few months of hard work done by our Chromium team, we can proudly say that we have nearly finished this task, which involved more than 1100 patches landed upstream after combining the patches that migrated the types inside Blink (see bug 978694) with those that tackled the rest of the Chromium repository (see bug 955171).

And by “nearly finished” I mean an overall progress of 99.21% according to the Migration to new mojo types spreadsheet where we track this effort, where Blink and //content have been fully migrated, and all the other directories, aggregated together, are at 98.64%, not bad!

On this regard, I’ve been also sending a bi-weekly status report mail to the chromium-mojo and platform-architecture-dev mailing lists for a while (see the latest report here), so make sure to subscribe there if you’re interested, even though those reports might not last much longer!

Now, back with our feet on the ground, the main roadblock at the moment preventing us from reaching 100% is //components/arc, whose migration needs to be agreed with the folks maintaining a copy of Chromium’s ARC mojo files for Android and ChromeOS. This is currently under discussion (see chromium-mojo ML and bug 1035484) and so I’m confident it will be something we’ll hopefully be able to achieve early next year.

Finally, and still related to this Mojo migrations, my colleague Shin and I took a “little detour” while working on this migration and focused for a while in the more specific task of migrating uses of Chromium’s InterfaceProvider to the new BrowserInterfaceBroker class. And while this was not a task as massive as the other migration, it was also very important because, besides fixing some problems inherent to the old InterfaceProvider API, it also blocked the migration to the new mojo types as InterfaceProvider did usually rely on the old types!


Architecture of the BrowserInterfaceBroker

Good news here as well, though: after having the two of us working on this task for a few weeks, we can proudly say that, today, we have finished all the 132 migrations that were needed and are now in the process of doing some after-the-job cleanup operations that will remove even more code from the repository! \o/

Attendance to conferences

This year was particularly busy for me in terms of conferences, as I did travel to a few events both as an attendee and a speaker. So, here’s a summary about that as well:

As usual, I started the year attending one of my favourite conferences of the year by going to FOSDEM 2019 in Brussels. And even though I didn’t have any talk to present in there, I did enjoy my visit like every year I go there. Being able to meet so many people and being able to attend such an impressive amount of interesting talks over the weekend while having some beers and chocolate is always great!

Next stop was Toronto, Canada, where I attended BlinkOn 10 on April 9th & 10th. I was honoured to have a chance to present a summary of the contributions that Igalia made to the Chromium Open Source project in the 12 months before the event, which was a rewarding experience but also quite an intense one, because it was a lightning talk and I had to go through all the ~10 slides in a bit under 3 minutes! Slides are here and there is also a video of the talk, in case you want to check how crazy that was.

Took a bit of a rest from conferences over the summer and then attended, also as usual, the Web Engines Hackfest that we at Igalia have been organising every single year since 2009. Didn’t have a presentation this time, but still it was a blast to attend it once again as an Igalian and celebrate the hackfest’s 10th anniversary sharing knowledge and experiences with the people who attended this year’s edition.

Finally, I attended two conferences in the Bay Area by mid November: first one was the Chrome Dev Summit 2019 in San Francisco on Nov 11-12, and the second one was BlinkOn 11 in Sunnyvale on Nov 14-15. It was my first time at the Chrome Dev Summit and I have to say I was fairly impressed by the event, how it was organised and the quality of the talks in there. It was also great for me, as a browsers developer, to see first hand what are the things web developers are more & less excited about, what’s coming next… and to get to meet people I would have never had a chance to meet in other events.

As for BlinkOn 11, I presented a 30 min talk about our work on the Onion Soup project, the Mojo migrations and improving Chromium’s code health in general, along with my colleague Antonio Gomes. It was basically a “extended” version of this post where we went not only through the tasks I was personally involved with, but also talked about other tasks that other members of our team worked on during this year, which include way many other things! Feel free to check out the slides here, as well as the video of the talk.

Wrapping Up

As you might have guessed, 2019 has been a pretty exciting and busy year for me work-wise, but the most interesting bit in my opinion is that what I mentioned here was just the tip of the iceberg… many other things happened in the personal side of things, starting with the fact that this was the year that we consolidated our return to Spain after 6 years living abroad, for instance.

Also, and getting back to work-related stuff here again, this year I also became accepted back at Igalia‘s Assembly after having re-joined this amazing company back in September 2018 after a 6-year “gap” living and working in the UK which, besides being something I was very excited and happy about, also brought some more responsibilities onto my plate, as it’s natural.

Last, I can’t finish this post without being explicitly grateful for all the people I got to interact with during this year, both at work and outside, which made my life easier and nicer at so many different levels. To all of you,  cheers!

And to everyone else reading this… happy holidays and happy new year in advance!

Working on the Chromium Servicification Project

Published / by mario

Igalia & ChromiumIt’s been a few months already since I (re)joined Igalia as part of its Chromium team and I couldn’t be happier about it: right since the very first day, I felt perfectly integrated as part of the team that I’d be part of and quickly started making my way through the -fully upstream- project that would keep me busy during the following months: the Chromium Servicification Project.

But what is this “Chromium servicification project“? Well, according to the Wiktionary the word “servicification” means, applied to computing, “the migration from monolithic legacy applications to service-based components and solutions”, which is exactly what this project is about: as described in the Chromium servicification project’s website, the whole purpose behind this idea is “to migrate the code base to a more modular, service-oriented architecture”, in order to “produce reusable and decoupled components while also reducing duplication”.

Doing so would not only make Chromium a more manageable project from a source code-related point of view and create better and more stable interfaces to embed chromium from different projects, but should also enable teams to experiment with new features by combining these services in different ways, as well as to ship different products based in Chromium without having to bundle the whole world just to provide a particular set of features. 

For instance, as Camille Lamy put it in the talk delivered (slides here) during the latest Web Engines Hackfest,  “it might be interesting long term that the user only downloads the bits of the app they need so, for instance, if you have a very low-end phone, support for VR is probably not very useful for you”. This is of course not the current status of things yet (right now everything is bundled into a big executable), but it’s still a good way to visualise where this idea of moving to a services-oriented architecture should take us in the long run.

Chromium Servicification Layers

With this in mind, the idea behind this project would be to work on the migration of the different parts of Chromium depending on those components that are being converted into services, which would be part of a “foundation” base layer providing the core services that any application, framework or runtime build on top of chromium would need.

As you can imagine, the whole idea of refactoring such an enormous code base like Chromium’s is daunting and a lot of work, especially considering that currently ongoing efforts can’t simply be stopped just to perform this migration, and that is where our focus is currently aimed at: we integrate with different teams from the Chromium project working on the migration of those components into services, and we make sure that the clients of their old APIs move away from them and use the new services’ APIs instead, while keeping everything running normally in the meantime.

At the beginning, we started working on the migration to the Network Service (which allows to run Chromium’s network stack even without a browser) and managed to get it shipped in Chromium Beta by early October already, which was a pretty big deal as far as I understand. In my particular case, that stage was a very short ride since such migration was nearly done by the time I joined Igalia, but still something worth mentioning due to the impact it had in the project, for extra context.

After that, our team started working on the migration of the Identity service, where the main idea is to encapsulate the functionality of accessing the user’s identities right through this service, so that one day this logic can be run outside of the browser process. One interesting bit about this migration is that this particular functionality (largely implemented inside the sign-in component) has historically been located quite high up in the stack, and yet it’s now being pushed all the way down into that “foundation” base layer, as a core service. That’s probably one of the factors contributing to making this migration quite complicated, but everyone involved is being very dedicated and has been very helpful so far, so I’m confident we’ll get there in a reasonable time frame.

If you’re curious enough, though, you can check this status report for the Identity service, where you can see the evolution of this particular migration, along with the impact our team had since we started working on this part, back on early October. There are more reports and more information in the mailing list for the Identity service, so feel free to check it out and/or subscribe there if you like.

One clarification is needed, tough: for now, the scope of this migrations is focused on using the public C++ APIs that such services expose (see //services/<service_name>/public/cpp), but in the long run the idea is that those services will also provide Mojo interfaces. That will enable using their functionality regardless of whether you’re running those services as part of the browser’s process, or inside their own & separate processes, which will then allow the flexibility that chromium will need to run smoothly and safely in different kind of environments, from the least constrained ones to others with a less favourable set of resources at their disposal.

And this is it for now, I think. I was really looking forward to writing a status update about what I’ve been up to in the past months and here it is, even though it’s not the shortest of all reports.

FOSDEM 2019

One last thing, though: as usual, I’m going to FOSDEM this year as well, along with a bunch of colleagues & friends from Igalia, so please feel free to drop me/us a line if you want to chat and/or hangout, either to talk about work-related matters or anything else really.

And, of course, I’d be also more than happy to talk about any of the open job positions at Igalia, should you consider applying. There are quite a few of them available at the moment for all kind of things (most of them available for remote work): from more technical roles such as graphicscompilersmultimedia, JavaScript engines, browsers (WebKitChromium, Web Platform) or systems administration (this one not available for remotes, though), to other less “hands-on” types of roles like developer advocatesales engineer or project manager, so it’s possible there’s something interesting for you if you’re considering to join such an special company like this one.

See you in FOSDEM!

Chromium Browser on xdg-app

Published / by mario / 7 Comments on Chromium Browser on xdg-app

Last week I had the chance to attend for 3 days the GNOME Software Hackfest, organized by Richard Hughes and hosted at the brand new Red Hat’s London office.

And besides meeting new people and some old friends (which I admit to be one of my favourite aspects about attending these kind of events), and discovering what it’s now my new favourite place for fast-food near London bridge, I happened to learn quite a few new things while working on my particular personal quest: getting Chromium browser to run as an xdg-app.

While this might not seem to be an immediate need for Endless right now (we currently ship a Chromium-based browser as part of our OSTree based system), this was definitely something worth exploring as we are now implementing the next version of our App Center (which will be based on GNOME Software and xdg-app). Chromium updates very frequently with fixes and new features, and so being able to update it separately and more quickly than the OS is very valuable.

Endless OS App Center
Screenshot of Endless OS’s current App Center

So, while Joaquim and Rob were working on the GNOME Software related bits and discussing aspects related to Continuous Integration with the rest of the crowd, I spent some time learning about xdg-app and trying to get Chromium to build that way which, unsurprisingly, was not an easy task.

Fortunately, the base documentation about xdg-app together with Alex Larsson’s blog post series about this topic (which I wholeheartedly recommend reading) and some experimentation from my side was enough to get started with the whole thing, and I was quickly on my way to fixing build issues, adding missing deps and the like.

Note that my goal at this time was not to get a fully featured Chromium browser running, but to get something running based on the version that we use use in Endless (Chromium 48.0.2564.82), with a couple of things disabled for now (e.g. chromium’s own sandbox, udev integration…) and putting, of course, some holes in the xdg-app configuration so that Chromium can access the system’s parts that are needed for it to function (e.g. network, X11, shared memory, pulseaudio…).

Of course, the long term goal is to close as many of those holes as possible using Portals instead, as well as not giving up on Chromium’s own sandbox right away (some work will be needed here, since `setuid` binaries are a no-go in xdg-app’s world), but for the time being I’m pretty satisfied (and kind of surprised, even) that I managed to get the whole beast built and running after 4 days of work since I started :-).

But, as Alberto usually says… “screencast or it didn’t happen!”, so I recorded a video yesterday to properly share my excitement with the world. Here you have it:


[VIDEO: Chromium Browser running as an xdg-app]

As mentioned above, this is work-in-progress stuff, so please hold your horses and manage your expectations wisely. It’s not quite there yet in terms of what I’d like to see, but definitely a step forward in the right direction, and something I hope will be useful not only for us, but for the entire Linux community as a whole. Should you were curious about the current status of the whole thing, feel free to check the relevant files at its git repository here.

Last, I would like to finish this blog post saying thanks specially to Richard Hughes for organizing this event, as well as the GNOME Foundation and Red Hat for their support in the development of GNOME Software and xdg-app. Finally, I’d also like to thank my employer Endless for supporting me to attend this hackfest. It’s been a terrific week indeed… thank you all!

Credit to Georges Stavracas

Credit to Georges Stavracas

Importing include paths in Eclipse

Published / by mario / 1 Comment on Importing include paths in Eclipse

First of all, let me be clear: no, I’m not trying to leave Emacs again, already got over that stage. Emacs is and will be my main editor for the foreseeable future, as it’s clear to me that there’s no other editor I feel more comfortable with, which is why I spent some time cleaning up my .emacs.d and making it more “manageable”.

But as much as like Emacs as my main “weapon”, I sometimes appreciate the advantages of using a different kind of beast for specific purposes. And, believe me or not, in the past 2 years I learned to love Eclipse/CDT as the best work-mate I know when I need some extra help to get deep inside of the two monster C++ projects that WebKit and Chromium are. And yes, I know Eclipse is resource hungry, slow, bloated… and whatnot; but I’m lucky enough to have fast SSDs and lots of RAM in my laptop & desktop machines, so that’s not really a big concern anymore for me (even though I reckon that indexing chromium in the laptop takes “quite some time”), so let’s move on :-)

However, there’s this one little thing that still bothers quite me a lot of Eclipse: you need to manually setup the include paths for the external dependencies not in a standard location that a C/C++ project uses, so that you can get certain features properly working such as code auto-completion, automatic error-checking features, call hierarchies… and so forth.

And yes, I know there is an Eclipse plugin adding support for pkg-config which should do the job quite well. But for some reason I can’t get it to work with Eclipse Mars, even though others apparently can use it there for some reason (and I remember using it with Eclipse Juno, so it’s definitely not a myth).

Anyway, I did not feel like fighting with that (broken?) plugin, and in the other hand I was actually quite inclined to play a bit with Python so… my quick and dirty solution to get over this problem was to write a small script that takes a list of package names (as you would pass them to pkg-config) and generates the XML content that you can use to import in Eclipse. And surprisingly, that worked quite well for me, so I’m sharing it here in case someone else finds it useful.

Using frogr as an example, I generate the XML file for Eclipse doing this:

  $ pkg-config-to-eclipse glib-2.0 libsoup-2.4 libexif libxml-2.0 \
        json-glib-1.0 gtk+-3.0 gstreamer-1.0 > frogr-eclipse.xml

…and then I simply import frogr-eclipse.xml from the project’s properties, inside the C/C++ General > Paths and Symbols section.

After doing that I get rid of all the brokenness caused by so many missing symbols and header files, I get code auto-completion nicely working back again and all those perks you would expect from this little big IDE. And all that without having to go through the pain of defining all of them one by one from the settings dialog, thank goodness!

Now you can quickly see how it works in the video below:


VIDEO: Setting up a C/C++ project in Eclipse with pkg-config-to-eclipse

This has been very helpful for me, hope it will be helpful to someone else too!