Add SkSourceGammaTreatment enum so we know how to create mips

src/effects/gradients/SkSweepGradient.cpp

Index: src/effects/gradients/SkSweepGradient.cpp
diff --git a/src/effects/gradients/SkSweepGradient.cpp b/src/effects/gradients/SkSweepGradient.cpp
index 4d210ed41be5121fd05221febe62fa70221be6d3..04476d618295e139e48a723bb58701d3dcfb0045 100644
--- a/src/effects/gradients/SkSweepGradient.cpp
+++ b/src/effects/gradients/SkSweepGradient.cpp
@@ -193,7 +193,7 @@ const GrFragmentProcessor* GrSweepGradient::TestCreate(GrProcessorTestData* d) {
                                                        colorCount));
     const GrFragmentProcessor* fp = shader->asFragmentProcessor(d->fContext,
                                                                 GrTest::TestMatrix(d->fRandom),
-                                                                NULL, kNone_SkFilterQuality);
+                                                                NULL, kNone_SkFilterQuality, false);
     GrAlwaysAssert(fp);
     return fp;
 }
@@ -230,7 +230,8 @@ const GrFragmentProcessor* SkSweepGradient::asFragmentProcessor(
                                                     GrContext* context,
                                                     const SkMatrix& viewM,
                                                     const SkMatrix* localMatrix,
-                                                    SkFilterQuality) const {
+                                                    SkFilterQuality,
+                                                    bool gammaCorrect) const {
 
     SkMatrix matrix;
     if (!this->getLocalMatrix().invert(&matrix)) {