Web Inspector: generalize InspectorDOMAgent::highlightRect() to highlightQuad()
https://bugs.webkit.org/show_bug.cgi?id=112911

Reviewed by Pavel Feldman.

- added Quad type and DOMAgent.highlightQuad() to protocol;
- retained DOMAgent.highlightRect(), but implement it via highlightQuad.

* inspector/Inspector.json:
* inspector/InspectorDOMAgent.cpp:
(WebCore::parseQuad):
(WebCore):
(WebCore::InspectorDOMAgent::highlightRect):
(WebCore::InspectorDOMAgent::highlightQuad):
(WebCore::InspectorDOMAgent::innerHighlightQuad):
* inspector/InspectorDOMAgent.h:
(InspectorDOMAgent):
* inspector/InspectorOverlay.cpp: Mostly just renames of rect to quad.
(WebCore::InspectorOverlay::paint):
(WebCore::InspectorOverlay::getHighlight):
(WebCore::InspectorOverlay::hideHighlight):
(WebCore::InspectorOverlay::highlightQuad):
(WebCore::InspectorOverlay::update):
(WebCore::InspectorOverlay::drawQuadHighlight):
(WebCore::InspectorOverlay::reportMemoryUsage):
* inspector/InspectorOverlay.h:
(InspectorOverlay):
* inspector/InspectorOverlayPage.html: Ditto.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147202 268f45cc-cd09-0410-ab3c-d52691b4dbfc