Initial support for GL_NV_path_renering. Experimental, there are still some issues to resolve, set gyp variable skia_nv_path_rendering=1 or build flag GR_GL_USE_NV_PATH_RENDERING to enable.

http://codereview.appspot.com/6349049/



git-svn-id: http://skia.googlecode.com/svn/trunk@4390 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrDrawState.h b/src/gpu/GrDrawState.h
index 81960fe..9132770 100644
--- a/src/gpu/GrDrawState.h
+++ b/src/gpu/GrDrawState.h
@@ -489,6 +489,7 @@
             }
             fDrawState = ds;
         }
+        bool isSet() const { return NULL != fDrawState; }
     private:
         GrDrawState* fDrawState;
         GrMatrix fSavedMatrix;