use Descriptor struct to encapsulate all the common paramaeters between our various gradient types. If we like it, might promote it to the public API.

BUG=
R=bsalomon@google.com

Review URL: https://codereview.chromium.org/15733007

git-svn-id: http://skia.googlecode.com/svn/trunk@9260 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
index abd974b..0066942 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -177,10 +177,8 @@
 SkTwoPointConicalGradient::SkTwoPointConicalGradient(
     const SkPoint& start, SkScalar startRadius,
     const SkPoint& end, SkScalar endRadius,
-    const SkColor colors[], const SkScalar pos[],
-    int colorCount, SkShader::TileMode mode,
-    SkUnitMapper* mapper)
-    : SkGradientShaderBase(colors, pos, colorCount, mode, mapper),
+    const Descriptor& desc)
+    : SkGradientShaderBase(desc),
     fCenter1(start),
     fCenter2(end),
     fRadius1(startRadius),