add drawArraysInstanced to caps

include/gpu/GrCaps.h

Index: include/gpu/GrCaps.h
diff --git a/include/gpu/GrCaps.h b/include/gpu/GrCaps.h
index 9ad20e53e41f3d123b3249f4832c760201109b78..0dd424b47fcdb5b99ddc034a754f7b027a9f148d 100644
--- a/include/gpu/GrCaps.h
+++ b/include/gpu/GrCaps.h
@@ -216,6 +216,10 @@ public:
         return fGeometryBufferMapThreshold;
     }
 
+    bool supportsInstancedDraws() const {
+        return fSupportsInstancedDraws;
+    }
+
 protected:
     /** Subclasses must call this at the end of their constructors in order to apply caps
         overrides requested by the client. Note that overrides will only reduce the caps never
@@ -235,6 +239,7 @@ protected:
     bool fCompressedTexSubImageSupport               : 1;
     bool fOversizedStencilSupport                    : 1;
     bool fTextureBarrierSupport                      : 1;
+    bool fSupportsInstancedDraws                     : 1;
 
     // Driver workaround
     bool fUseDrawInsteadOfClear                      : 1;