Use subject principal as triggering principal in <video>/<audio> "src"
attribute. We deviate from Mozilla here because we do not worry
about content isolation principals in Page Info.
In order to tailor certain security checks to the caller that is
attempting to load a particular piece of content, we need to be able to
attach an appropriate triggering principal to the corresponding requests.
Since most HTML content is loaded based on attribute values, this means
capturing the subject principal of the caller who sets those attributes,
which in turn means we need to make it available to `AfterSetAttr` hooks
on all relevant element types.
Since these are just interpreted comments, there's 0 impact on actual code.
This removes all lines that match /* vim: set(.*)tw=80: */ with S&R -- there are
a few others scattered around which will be removed manually in a second part.
Unless a user is debugging media errors, this detail is unnecessary to report
and could include sensitive data which could be abused by third-party
requesters. This aligns it with the standard success/error paradigms in normal
browsing situations.
* Moves side effects of nsGenericHTMLElement and Element's SetAttr, UnsetAttr, and ParseAttribute functions to the corresponding BeforeSetAttr and AfterSetAttr functions
* Moves side effects of HTMLAnchorElement's SetAttr, UnsetAttr, and ParseAttribute functions to the corresponding BeforeSetAttr and AfterSetAttr functions
* Moves side effects of HTMLImageElement's SetAttr function to the corresponding BeforeSetAttr and AfterSetAttr functions
* Moves side effects of SetAttr, UnsetAttr, and ParseAttribute functions to BeforeSetAttr and AfterSetAttr
Tag #1375
https://bugzilla.mozilla.org/show_bug.cgi?id=1244768
I happened to find an older version of the promise-based media playback patch in Bugzilla, the one that was originally submitted for review. It had the DocShell changes I already knew how to deal with, and had fewer of the audio wrapper and nsISupports changes that were confusing me in the later patch. I was able to do a better job getting this back into a UXP-appropriate configuration than I could have with the final version.
I'm honestly still a little unsure about some of the minor refactoring done in the patch itself, insisting on already_AddRefed promises and such, but I don't really know how to avoid those completely. Still, I think it's better than it was.
This creates a number of stubs and leaves some surrounding code that may be irrelevant (eg. recorded time stamps, status variables).
Stub resolution/removal should be a follow-up to this.
- Checks for restricted or encrypted content
- Dispatching 'encrypted' events
- Dispatching 'key needed' events
- HTML Media Element media keys system
- EME telemetry
- HTML Media Element EME API
This is the main bulk for #26, isolating EME-specific code.