Implement path cover with nv_path_rendering

src/gpu/gl/GrGpuGL_program.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGpuGL.h"
 
 #include "GrEffect.h"
@@ skipping 234 matching lines @@
                                &coverageStages,
                                &desc);
 
         fCurrentProgram.reset(fProgramCache->getProgram(desc,
                                                         colorStages.begin(),
                                                         coverageStages.begin()));
         if (NULL == fCurrentProgram.get()) {
             SkDEBUGFAIL("Failed to create program!");
             return false;
         }
+
+        SkASSERT(kFillPath_DrawType != type || !fCurrentProgram->hasVertexShader());
+
         fCurrentProgram.get()->ref();
 
         GrGLuint programID = fCurrentProgram->programID();
         if (fHWProgramID != programID) {
             GL_CALL(UseProgram(programID));
             fHWProgramID = programID;
         }
 
         fCurrentProgram->overrideBlend(&srcCoeff, &dstCoeff);
         this->flushBlend(kDrawLines_DrawType == type, srcCoeff, dstCoeff);
@@ skipping 106 matching lines @@
                              GrGLAttribTypeToLayout(attribType).fType,
                              GrGLAttribTypeToLayout(attribType).fNormalized,
                              stride,
                              reinterpret_cast<GrGLvoid*>(
                              vertexOffsetInBytes + vertexAttrib->fOffset));
         }
 
         attribState->disableUnusedArrays(this, usedAttribArraysMask, false);
     }
 }