Add optional data parameter to createBuffer

src/gpu/vk/GrVkGpu.h

Index: src/gpu/vk/GrVkGpu.h
diff --git a/src/gpu/vk/GrVkGpu.h b/src/gpu/vk/GrVkGpu.h
index 5872f18671972415e5d595472fa51b57f1e0c9ad..76b18ac71e70af891c8bb3c661f04fbcec868d94 100644
--- a/src/gpu/vk/GrVkGpu.h
+++ b/src/gpu/vk/GrVkGpu.h
@@ -129,7 +129,8 @@ private:
                                               GrWrapOwnership) override;
     GrRenderTarget* onWrapBackendTextureAsRenderTarget(const GrBackendTextureDesc&) override { return NULL; }
 
-    GrBuffer* onCreateBuffer(size_t size, GrBufferType type, GrAccessPattern) override;
+    GrBuffer* onCreateBuffer(size_t size, GrBufferType type, GrAccessPattern,
+                             const void* data) override;
 
     void onClear(GrRenderTarget*, const SkIRect& rect, GrColor color) override;