Move CanvasGradient and CanvasPattern in the union of CanvasStyle
https://bugs.webkit.org/show_bug.cgi?id=115759

Patch by Benjamin Poulain <bpoulain@apple.com> on 2013-05-07
Reviewed by Andreas Kling.

The Gradient and Pattern are exclusive with the other values, but they
were left out of the union because they are ref-counted.

This patch moves them in the union, and simply does the ref-counting manually.

* html/canvas/CanvasStyle.cpp:
(WebCore::CanvasStyle::CanvasStyle):
(WebCore::CanvasStyle::~CanvasStyle):
* html/canvas/CanvasStyle.h:
(CanvasStyle):
(WebCore::CanvasStyle::canvasGradient):
(WebCore::CanvasStyle::canvasPattern):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149696 268f45cc-cd09-0410-ab3c-d52691b4dbfc