Make ImageResourceObserver overrides private in StyleFetchedImage

Nothing should call these through a StyleFetchedImage, so we can make
these private. Add a comment about the overrides (also in
StyleFetchedImageSet).

Change-Id: I564d9603a77cf2452c504e3150f49dd11ea14053
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1824276Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#700298}

third_party/blink/renderer/core/style/style_fetched_image.h

@@ -61,8 +61,6 @@ class StyleFetchedImage final : public StyleImage,
   bool HasIntrinsicSize() const override;
   void AddClient(ImageResourceObserver*) override;
   void RemoveClient(ImageResourceObserver*) override;
-  void ImageNotifyFinished(ImageResourceContent*) override;
-  bool GetImageAnimationPolicy(ImageAnimationPolicy&) override;
   String DebugName() const override { return "StyleFetchedImage"; }
   scoped_refptr<Image> GetImage(const ImageResourceObserver&,
                                 const Document&,
@@ -81,6 +79,10 @@ class StyleFetchedImage final : public StyleImage,
   bool IsEqual(const StyleImage&) const override;
   void Dispose();
 
+  // ImageResourceObserver overrides
+  void ImageNotifyFinished(ImageResourceContent*) override;
+  bool GetImageAnimationPolicy(ImageAnimationPolicy&) override;
+
   Member<ImageResourceContent> image_;
   Member<const Document> document_;
   const KURL url_;

third_party/blink/renderer/core/style/style_fetched_image_set.h

@@ -85,6 +85,7 @@ class StyleFetchedImageSet final : public StyleImage,
   bool IsEqual(const StyleImage& other) const override;
   void Dispose();
 
+  // ImageResourceObserver overrides
   String DebugName() const override { return "StyleFetchedImageSet"; }
 
   Member<ImageResourceContent> best_fit_image_;