Add 'float FloatPoint::slopeAngleRadians()'
https://bugs.webkit.org/show_bug.cgi?id=105997

Patch by Steve Block <steveblock@chromium.org> on 2013-01-04
Reviewed by Stephen White.

Refactoring only, no functional change.

* platform/graphics/FloatPoint.cpp:
(WebCore::FloatPoint::slopeAngleRadians):
(WebCore):
* platform/graphics/FloatPoint.h:
Add 'float FloatPoint::slopeAngleRadians() const'
* platform/graphics/PathTraversalState.cpp:
(WebCore::PathTraversalState::processSegment):
* rendering/svg/SVGMarkerData.h:
(WebCore::SVGMarkerData::currentAngle):
* svg/SVGPathParser.cpp:
(WebCore::SVGPathParser::decomposeArcToCubic):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@138800 268f45cc-cd09-0410-ab3c-d52691b4dbfc