added support for PLS path rendering

src/gpu/batches/GrDrawBatch.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDrawBatch.h"
 
 GrDrawBatch::GrDrawBatch(uint32_t classID) : INHERITED(classID), fPipelineInstalled(false) { }
 
 GrDrawBatch::~GrDrawBatch() {
     if (fPipelineInstalled) {
         this->pipeline()->~GrPipeline();
     }
 }
 
 void GrDrawBatch::getPipelineOptimizations(GrPipelineOptimizations* opt) const {
     GrInitInvariantOutput color;
     GrInitInvariantOutput coverage;
+    opt->fOverrides.fUsePLSDstRead = false;
     this->computePipelineOptimizations(&color, &coverage, &opt->fOverrides);
     opt->fColorPOI.initUsingInvariantOutput(color);
     opt->fCoveragePOI.initUsingInvariantOutput(coverage);
 }
 
 bool GrDrawBatch::installPipeline(const GrPipeline::CreateArgs& args) {
     GrXPOverridesForBatch overrides;
     void* location = fPipelineStorage.get();
     if (!GrPipeline::CreateAt(location, args, &overrides)) {
         return false;
     }
     this->initBatchTracker(overrides);
     fPipelineInstalled = true;
     return true;
 }