Make max number of vertex attributes be checked dynamically

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 161ca5c35d42f0713d62a2aa66c0466bac99890f..082f53f830d69bef4fa0234194093feef51ce22a 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -380,8 +380,9 @@ public:
 
     // We pass in an array of meshCount GrMesh to the draw. The backend should loop over each
     // GrMesh object and emit a draw for it. Each draw will use the same GrPipeline and
-    // GrPrimitiveProcessor.
-    void draw(const GrPipeline&,
+    // GrPrimitiveProcessor. This may fail if the draw would exceed any resource limits (e.g.
+    // number of vertex attributes is too large).
+    bool draw(const GrPipeline&,
               const GrPrimitiveProcessor&,
               const GrMesh*,
               int meshCount);