Bug 279265 – Support `referrerPolicy` for SVG <a> element

• Component: DOM
• Status: NEW

[Ahmad Saleem]

Hi Team,

While looking into failing SVG idlharness tests, I noticed that we fail `referrerpolicy` related tests, I don't know is it easy to fix or not but this does make us pass tests:

WPT Test Case: http://wpt.live/svg/idlharness.window.html

> SVGAElement interface: objects.a must inherit property "referrerPolicy" with the proper type	
> SVGAElement interface: attribute referrerPolicy	

Progress after below and only Firefox has support for it so far:

In `SVGAElement.idl`:

[CEReactions=NotNeeded, ImplementedAs=referrerPolicyForBindings] attribute [AtomString] DOMString referrerPolicy;

In `SVGAElement.h`:

void setReferrerPolicyForBindings(const AtomString&);
String referrerPolicyForBindings() const;
ReferrerPolicy referrerPolicy() const;

In `SVGAElement.cpp`:

void SVGAElement::setReferrerPolicyForBindings(const AtomString& value)
{
    setAttributeWithoutSynchronization(HTMLNames::referrerpolicyAttr, value);
}

String SVGAElement::referrerPolicyForBindings() const
{
    return referrerPolicyToString(referrerPolicy());
}

ReferrerPolicy SVGAElement::referrerPolicy() const
{
    return parseReferrerPolicy(attributeWithoutSynchronization(HTMLNames::referrerpolicyAttr), ReferrerPolicySource::ReferrerPolicyAttribute).value_or(ReferrerPolicy::EmptyString);
}

___

Above does not add logic around `handleClick`, which is in HTMLAnchorElemnet.cpp and I also leverage `HTMLNames` similar in feedback from Anne in leveraging as much as `HTMLNames` rather than reintroducing same thing in SVGNames.

Just raising to get feedback and input.

Thanks!

[Radar WebKit Bug Importer]

<rdar://problem/135952757>