Bug 735031 was to update the Firefox fullscreen implementation to allow SVG elements to receive fullscreen mode.

An overview of the relationship between DOM Elements

This is not a complete diagram, there are a bunch more elements inheriting from nsIDOMHTML/SVG/XULElement. However, It gives a nice visual representation showing that not all DOMElements are HTMLElements.

Problem

Only HTML Elements were allowed to receive fullscreen mode.
SVG Elements didn’t know about mozRequestFullScreen since the implementation was done only for HTML Elements

Requesting mozFullScreen on a SVG element would give this error:

TypeError: svgElement.mozRequestFullScreen is not a function

The IDL declarion for mozRequestFullScreen was on:

dom/interface/ html /nsIDOMHTMLElement.idl

And

MozRequestFullScreen

was implemented on:

content/html/content/src/nsGenericHTMLElement.cpp

Solution

The solution was to move the declaration of mozRequestFullScreen to:

dom/interfaces/core/nsIDOMElement.idl

And the definition:

content/base/src/nsGenericElement.cpp

Now both HTML and SVG elements can request fullscreen mode.

Bug
Diff

Notes

Since this fix had to change some IDLs, their UUID had to be updated. However, in this case, because the base IDL for all DOMElements was changed, the UUIDS for all the IDLs inheriting from nsIDOMElement had to be updated as well. The problem is that there are around 150 IDLs inheriting from nsIDOMElement, and to update each one by hand would have been CRAZY!
Luckly, somebody must have faced this problem before and created a script to update the UUID of IDLs and all its children.

update-uuids To run the script:

update-uuids . nsIDOMElement nsIDOMDocument

The output:

nsIDOMElement because it was given on command line
f561753a-1d4f-40c1-b147-ea955fc6fd94 -> a652db92-f8d4-47e0-bf8f-1ad72e6c083f
nsIDOMDocument because it was given on command line
d7cdd08e-1bfd-4bc3-9742-d66586781ee2 -> ff3125e0-b1b5-467f-84ad-1d1eeafed595
nsIDOMHTMLElement because it inherits from nsIDOMElement
3de9f8c1-5d76-4d2e-b6b9-334c6eb0c113 -> 5b703ce7-e551-41fa-b465-ff94aa3bdc66
nsIDOMXULElement because it inherits from nsIDOMElement
5e0a7c2c-fdb6-459d-a67b-549181218c31 -> 42e74ec0-75c7-422c-b564-f853e3cbbb8b
nsIDOMSVGElement because it inherits from nsIDOMElement
dbb1b49c-dce5-43fe-97ea-e249b5620aa2 -> d2900917-e0ce-4eb8-aaf9-7e021d45472a
nsIDOMXMLDocument because it inherits from nsIDOMDocument
b53a4bab-0065-468b-810a-4c4659a04f00 -> b76ca016-46e8-4ee2-be3d-5b08b29afb72
….

.. Updated ./dom/interfaces/svg/nsIDOMSVGLineElement.idl with 1 changes
Updated ./dom/interfaces/svg/nsIDOMSVGStopElement.idl with 1 changes
Updated ./dom/interfaces/svg/nsIDOMSVGGElement.idl with 1 changes
Updated ./dom/interfaces/svg/nsIDOMSVGPatternElement.idl with 1 changes
Updated ./dom/interfaces/svg/nsIDOMSVGForeignObjectElem.idl with 1 changes
….

.

Originals are in *.idlbak