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

src/gpu/gl/GrGLProgramDesc.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 "GrGLProgramDesc.h"
 
 #include "GrGLProcessor.h"
 #include "GrProcessor.h"
@@ skipping 125 matching lines @@
     // make sure any padding in the header is zeroed.
     memset(header, 0, kHeaderSize);
 
     if (pipeline.readsFragPosition()) {
         header->fFragPosKey =
                 GrGLFragmentShaderBuilder::KeyForFragmentPosition(pipeline.getRenderTarget(),
                                                                   gpu->glCaps());
     } else {
         header->fFragPosKey = 0;
     }
-
+    header->fSnapVerticesToPixelCenters = pipeline.snapVerticesToPixelCenters();
     header->fColorEffectCnt = pipeline.numColorFragmentStages();
     header->fCoverageEffectCnt = pipeline.numCoverageFragmentStages();
     glDesc->finalize();
     return true;
 }