Make non-AA hairline stroke rects snap to pixels centers so they close.

src/gpu/GrPipeline.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 "GrPipeline.h"
 
 #include "GrBatch.h"
@@ skipping 46 matching lines @@
     fStencilSettings = pipelineBuilder.getStencil();
     fDrawFace = pipelineBuilder.getDrawFace();
 
     fFlags = 0;
     if (pipelineBuilder.isHWAntialias()) {
         fFlags |= kHWAA_Flag;
     }
     if (pipelineBuilder.isDither()) {
         fFlags |= kDither_Flag;
     }
+    if (pipelineBuilder.snapVerticesToPixelCenters()) {
+        fFlags |= kSnapVertices_Flag;
+    }
 
     int firstColorStageIdx = colorPOI.firstEffectiveStageIndex();
 
     // TODO: Once we can handle single or four channel input into coverage stages then we can use
     // GrPipelineBuilder's coverageProcInfo (like color above) to set this initial information.
     int firstCoverageStageIdx = 0;
 
     GrXferProcessor::BlendInfo blendInfo;
     fXferProcessor->getBlendInfo(&blendInfo);
 
@@ skipping 76 matching lines @@
     SkASSERT(this->numFragmentStages() == that.numFragmentStages());
     for (int i = 0; i < this->numFragmentStages(); i++) {
 
         if (this->getFragmentStage(i) != that.getFragmentStage(i)) {
             return false;
         }
     }
     return true;
 }