[S.P.] Don't draw frames of animated images that are offscreen.

Source/core/layout/LayoutImage.h

Index: Source/core/layout/LayoutImage.h
diff --git a/Source/core/layout/LayoutImage.h b/Source/core/layout/LayoutImage.h
index 4f6be49c878c7778b5e064894cab6a1e799eb0d8..70cc25cb3784a510ad8e9b53dacb282c8856a1c5 100644
--- a/Source/core/layout/LayoutImage.h
+++ b/Source/core/layout/LayoutImage.h
@@ -84,6 +84,8 @@ protected:
 
     virtual bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectLayoutImage || LayoutReplaced::isOfType(type); }
 
+    virtual PaintInvalidationReason invalidatePaintIfNeeded(const PaintInvalidationState&, const LayoutBoxModelObject&) override;
+
 private:
     virtual bool isImage() const override { return true; }
 
@@ -106,6 +108,9 @@ private:
     // Update the size of the image to be rendered. Object-fit may cause this to be different from the CSS box's content rect.
     void updateInnerContentRect();
 
+    // The given rect is in the local coordinate space of the LayoutImage.
+    bool rectIntersectsVisibleViewport(const LayoutRect&);
+
     // Text to display as long as the image isn't available.
     OwnPtr<LayoutImageResource> m_imageResource;
     bool m_didIncrementVisuallyNonEmptyPixelCount;