Set GeometryBufferMapThreshold defaults

include/gpu/GrCaps.h

Index: include/gpu/GrCaps.h
diff --git a/include/gpu/GrCaps.h b/include/gpu/GrCaps.h
index 25f3caadeda59e89d8317f089578d3038e1c5084..4bed33020655a4da48e605810fcee3ab9de5b3d6 100644
--- a/include/gpu/GrCaps.h
+++ b/include/gpu/GrCaps.h
@@ -200,6 +200,7 @@ public:
     }
 
     size_t geometryBufferMapThreshold() const {
+        SkASSERT(fGeometryBufferMapThreshold >= 0);
         return fGeometryBufferMapThreshold;
     }
 
@@ -226,6 +227,7 @@ protected:
 
     BlendEquationSupport fBlendEquationSupport;
     uint32_t fMapBufferFlags;
+    int fGeometryBufferMapThreshold;
 
     int fMaxRenderTargetSize;
     int fMaxTextureSize;
@@ -238,7 +240,6 @@ protected:
 private:
     bool fSupressPrints : 1;
     bool fDrawPathMasksToCompressedTextureSupport : 1;
-    size_t fGeometryBufferMapThreshold;
 
     typedef SkRefCnt INHERITED;
 };