Move geometry generation out of RenderSVGResource*::postApplyResource

The code-paths that will operate on RenderSVGResources that are
paint-servers are quite easily distinguishable from those where other
resources are involved - and because all paint-servers have the same kind
of geometry generation it's trivially hoistable into the relevant
callsites.
This allows the argument list of postApplyResource to be shortened
(removing |path|, |shape| and |resourceMode| since they are now unused).
Since all callers of the hoisted function (fillOrStrokePrimitive) passes
either a |shape| or a |path| - but never both, we can split this method into
its two logical parts.
Doing this however reveal that the |shape| variant can be trivially folded
into it's callers since they will always end up calling the same method.
This means that fillOrStrokePrimitive is replaced with/transformed into
fillOrStrokePath.

Review URL: https://codereview.chromium.org/571923002

git-svn-id: svn://svn.chromium.org/blink/trunk@182004 bbb929c8-8fbe-4397-9dbb-9b2b20218538