[Mac, iOS] Adjust pagination behavior for Mail.app printing use

[Brent Fulgham]

Certain uses of iframe elements in WebKit clients can cause undesirable printing behavior. WebKit attempts to keep all contents of an iframe together on the same page, but in some cases that does not produce good looking print output.

This bug provides a new setting that allows the default printing behavior to be overridden.

[Brent Fulgham]

<rdar://problem/14912763>

[Brent Fulgham]

Created attachment 246537 [details]
Patch

[Brent Fulgham]

Created attachment 246541 [details]
Patch

[Anders Carlsson]

Comment on attachment 246541 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=246541&action=review

> Source/WebCore/rendering/RenderBlockFlow.cpp:1617
> +static const AtomicString& messageContainerName()
> +{
> +    static NeverDestroyed<AtomicString> messageContainerNameString("messageContentContainer", AtomicString::ConstructFromLiteral);
> +    return messageContainerNameString;
> +}

It's bad to use AtomicString inside NeverDestroyed since they are different for different threads. I'd just use a literal in the function below instead.

[Brent Fulgham]

Created attachment 246545 [details]
Patch

[Brent Fulgham]

(In reply to comment #4)
> Comment on attachment 246541 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=246541&action=review
> 
> > Source/WebCore/rendering/RenderBlockFlow.cpp:1617
> > +static const AtomicString& messageContainerName()
> > +{
> > +    static NeverDestroyed<AtomicString> messageContainerNameString("messageContentContainer", AtomicString::ConstructFromLiteral);
> > +    return messageContainerNameString;
> > +}
> 
> It's bad to use AtomicString inside NeverDestroyed since they are different
> for different threads. I'd just use a literal in the function below instead.

OK!

[Brent Fulgham]

Committed r180076: <http://trac.webkit.org/changeset/180076>