Remove unnecessary assert in GrBatchAtlas.

src/gpu/GrBatchAtlas.cpp

Index: src/gpu/GrBatchAtlas.cpp
diff --git a/src/gpu/GrBatchAtlas.cpp b/src/gpu/GrBatchAtlas.cpp
index 8cc6f6181149f3223c78e06f79255c7289fccd57..e0828a4e6a1c6181d1dad002b569c098e6af2dc9 100644
--- a/src/gpu/GrBatchAtlas.cpp
+++ b/src/gpu/GrBatchAtlas.cpp
@@ -220,8 +220,6 @@ bool GrBatchAtlas::addToAtlas(AtlasID* id, GrDrawBatch::Target* target,
         return false;
     }
 
-    SkASSERT(!plot->unique());  // The GrPlotUpdater should have a ref too
-
     this->processEviction(plot->id());
     fPlotList.remove(plot);
     SkAutoTUnref<BatchPlot>& newPlot = fPlotArray[plot->index()];