Move texture drawing utility method to SkGpuDevice

src/gpu/SkGpuDevice.h

Index: src/gpu/SkGpuDevice.h
diff --git a/src/gpu/SkGpuDevice.h b/src/gpu/SkGpuDevice.h
index 5bf074d120330de0e887a3e9e7c057dcb462575e..219b76573b1b71585140b79d01725b2393de07da 100644
--- a/src/gpu/SkGpuDevice.h
+++ b/src/gpu/SkGpuDevice.h
@@ -140,6 +140,9 @@ public:
 
     static SkImageFilter::Cache* NewImageFilterCache();
 
+    // for debugging purposes only
+    void drawTexture(GrTexture*, const SkRect& dst, const SkPaint&);
+
 protected:
     bool onReadPixels(const SkImageInfo&, void*, size_t, int, int) override;
     bool onWritePixels(const SkImageInfo&, const void*, size_t, int, int) override;