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

src/gpu/gl/GrGLProgramDesc.cpp

Index: src/gpu/gl/GrGLProgramDesc.cpp
diff --git a/src/gpu/gl/GrGLProgramDesc.cpp b/src/gpu/gl/GrGLProgramDesc.cpp
index 96a8ada09e79bc8bc0f10c2e2b29dc4629618706..87e7f2d834c3641384f4f62d327fe613528b8843 100644
--- a/src/gpu/gl/GrGLProgramDesc.cpp
+++ b/src/gpu/gl/GrGLProgramDesc.cpp
@@ -143,7 +143,7 @@ bool GrGLProgramDescBuilder::Build(GrProgramDesc* desc,
     } else {
         header->fFragPosKey = 0;
     }
-
+    header->fSnapVerticesToPixelCenters = pipeline.snapVerticesToPixelCenters();
     header->fColorEffectCnt = pipeline.numColorFragmentStages();
     header->fCoverageEffectCnt = pipeline.numCoverageFragmentStages();
     glDesc->finalize();