Chromium Flatpak

Extension points

To avoid having to expose more of the host filesystem in the sandbox but still allowing extending Chromium, the org.chromium.Chromium.Extension extension point is defined.

This extension point is currently on version '1' and will expose any extension manifests under the extensions subdirectory, policy files under policies/managed and policies/recommended, and native messaging host manifests under native-messaging-hosts.

Legacy extension points

This application also supports two other extension points: org.chromium.Chromium.Policy and org.chromium.Chromium.NativeMessagingHost. These primarily exist for compatibility reasons and should not be used.

Using extension points

Extension points can be provided as regular flatpaks and an example is provided under examples/policies/google-safe-search. Important to note that extension points' name must follow the syntax of Extension.<id>, where <id> is a generic id for this specific extension point.

Flatpak also supports “unmanaged extensions”, allowing loading extensions installed into /var/lib/flatpak/extension and $XDG_DATA_HOME/flatpak/extension. This can be useful for example to allow system administrators to expose system installed policies, extensions, etc.

One example of such "unmanaged extension" could be an extension point that exposes all system policies installed under /etc/chromium-browser/policies/{managed,recommended}. This could be done for example by creating an extension point under /var/lib/flatpak/extension/org.chromium.Chromium.Extension.system-policies, with /var/lib/flatpak/extension/org.chromium.Chromium.Extension.system-policies/<arch>/<version> being a symlink to /etc/chromium-browser. Note that <version> must match the extension point version.

Also important to note that in the example above one would not be able to symlink the actual policy file directly, as otherwise flatpak would not be able to resolve the symlink when bind mounting the extension point.

Building and updating

CroFT is used to manage the patches in this repository and work with a build environment.

Build arguments to pass to gn

# Not required but makes builds faster.
use_lld = true
# NaCL hasn't been tested and is being removed from Linux builds.
enable_nacl = false
# Unrelated to Flatpak but helps speed up builds.
blink_symbol_level = 0
# Outdated
use_gnome_keyring = false
# Not supported
use_sysroot = false