Bug 258781

Hi Team, While going through Blink's commit, I came across where they moved 'markers' to AtomString: Blink Commit: https://chromium.googlesource.com/chromium/blink/+/599ce87bff640bcb680db17ed7fff3c482742483 WebKit Source: < SVGRenderStyle.h > https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyle.h#L82-L84 , https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyle.h#L127-L129 , https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyle.h#L169-L171 , https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyle.h#L440 , https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyle.h#L446 , https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyle.h#L452 < SVGRenderStyleDefs.h > https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/rendering/style/SVGRenderStyleDefs.h#L276-L278 < CSSPropertyAnimation.cpp > https://github.com/WebKit/WebKit/blob/68167894313ea917099c52a92e4b1ab03a277abf/Source/WebCore/animation/CSSPropertyAnimation.cpp#L3765-L3767 etc. I just wanted to raise, so if there is any benefits, we can also change to AtomString but if not, we can mark this as 'RESOLVED INVALID'. I am CCing Darin because I have seen his Webki-Dev mailgroup on String vs AtomString so I think he can give some good insight. Thanks!