Reviewed by Andreas Kling.

The Element::document is a simpler faster alternative to Element::ownerDocument.
The only behavior difference between the two is that ownerDocument returns 0 when
called on a Document.

* html/HTMLMediaElement.cpp:
(WebCore::HTMLMediaElement::supportsFocus): Call document instead of ownerDocument.
(WebCore::HTMLMediaElement::mediaPlayerOwningDocument): Removed null checking of
document and call to ownerDocument, since ownerDocument will never return non-null
if document returns null.
(WebCore::HTMLMediaElement::mediaPlayerSawUnsupportedTracks): Call document instead
of ownerDocument.

* inspector/DOMEditor.cpp:
(WebCore::DOMEditor::SetOuterHTMLAction::perform): Call document instead of ownerDocument.

* inspector/InspectorCSSAgent.cpp:
(WebCore::InspectorCSSAgent::getMatchedStylesForNode): Call document instead of ownerDocument.
(WebCore::InspectorCSSAgent::forcePseudoState): Call document instead of ownerDocument.
(WebCore::InspectorCSSAgent::resetPseudoStates): Call document instead of ownerDocument.

* inspector/InspectorDOMAgent.cpp:
(WebCore::InspectorDOMAgent::setOuterHTML): Call document instead of expression that
does the same thing in a roundabout way.
(WebCore::InspectorDOMAgent::focusNode): Call document instead of ownerDocument.
(WebCore::InspectorDOMAgent::resolveNode): Call document instead of expression that
does the same thing in a roundabout way.

* page/DragController.cpp:
(WebCore::DragController::concludeEditDrag): Call document instead of ownerDocument.

* svg/SVGElementInstance.cpp:
(WebCore::SVGElementInstance::ownerDocument): Call document instead of ownerDocument.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154225 268f45cc-cd09-0410-ab3c-d52691b4dbfc