Enable vertexless shading when path rendering is supported

src/gpu/GrOvalRenderer.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrOvalRenderer.h"
 
 #include "GrEffect.h"
@@ skipping 334 matching lines @@
 
     static const char* Name() { return "DIEllipseEdge"; }
 
     inline Mode getMode() const { return fMode; }
 
     class GLEffect : public GrGLEffect {
     public:
         GLEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
         : INHERITED (factory) {}
 
+        virtual bool requiresVertexShader(const GrDrawEffect&) const SK_OVERRIDE { return true; }
+
         virtual void emitCode(GrGLShaderBuilder* builder,
                               const GrDrawEffect& drawEffect,
                               EffectKey key,
                               const char* outputColor,
                               const char* inputColor,
                               const TextureSamplerArray& samplers) SK_OVERRIDE {
             GrGLShaderBuilder::VertexBuilder* vertexBuilder = builder->getVertexBuilder();
             SkASSERT(NULL != vertexBuilder);
 
             const DIEllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<DIEllipseEdgeEffect>();
@@ skipping 776 matching lines @@
         }
 
         // drop out the middle quad if we're stroked
         int indexCnt = isStroked ? GR_ARRAY_COUNT(gRRectIndices)-6 : GR_ARRAY_COUNT(gRRectIndices);
         target->setIndexSourceToBuffer(indexBuffer);
         target->drawIndexed(kTriangles_GrPrimitiveType, 0, 0, 16, indexCnt, &bounds);
     }
 
     return true;
 }