Use transfer buffer for BatchAtlas texture copies

src/gpu/gl/GrGLGpu.h

Index: src/gpu/gl/GrGLGpu.h
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index 20616e452db03f97745ab6e2c2a72ff45fb4a3f6..db7a09721eeb1afefa596d445630daa4dd808d3c 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -144,6 +144,10 @@ public:
 
     void finishDrawTarget() override;
 
+    GrFence SK_WARN_UNUSED_RESULT insertFence() const override;
+    bool waitFence(GrFence) const override;
+    void deleteFence(GrFence) const override;
+
 private:
     GrGLGpu(GrGLContext* ctx, GrContext* context);
 
@@ -209,7 +213,7 @@ private:
                        GrPixelConfig config,
                        const SkTArray<GrMipLevel>& texels) override;
 
-    bool onTransferPixels(GrSurface*,
+    bool onTransferPixels(GrTexture*,
                           int left, int top, int width, int height,
                           GrPixelConfig config, GrBuffer* transferBuffer,
                           size_t offset, size_t rowBytes) override;