Delay SVGImage animations reset while being updated.

third_party/WebKit/Source/core/svg/graphics/SVGImage.h

Index: third_party/WebKit/Source/core/svg/graphics/SVGImage.h
diff --git a/third_party/WebKit/Source/core/svg/graphics/SVGImage.h b/third_party/WebKit/Source/core/svg/graphics/SVGImage.h
index ea98cf224aa79547f8541b11b5603b09fae1b47f..3de118dc6827ff866f6c5fe93f7564a3ed94fee0 100644
--- a/third_party/WebKit/Source/core/svg/graphics/SVGImage.h
+++ b/third_party/WebKit/Source/core/svg/graphics/SVGImage.h
@@ -83,10 +83,25 @@ public:
 
     bool hasIntrinsicDimensions() const;
 
+    // While updating the image's animations the underlying ImageResource needs
+    // to be kept alive and it should not trigger resetting of animations while
+    // the update runs. This scope object takes care of the details.
+    class UpdateAnimationScope {
+        STACK_ALLOCATED();
+    public:
+        explicit UpdateAnimationScope(SVGImage*);
+        ~UpdateAnimationScope();
+
+    private:
+        SVGImage* m_image;
+        Member<ImageObserver> m_imageObserver;
+    };
+
 private:
     friend class AXLayoutObject;
     friend class SVGImageChromeClient;
     friend class SVGImageForContainer;
+    friend class UpdateAnimationScope;
 
     ~SVGImage() override;
 
@@ -113,6 +128,15 @@ private:
     void drawInternal(SkCanvas*, const SkPaint&, const FloatRect& fromRect, const FloatRect& toRect, RespectImageOrientationEnum,
         ImageClampingMode, const KURL&);
 
+    void enterNoResetAnimationsScope()
+    {
+        // No known need for supporting nested invocations.
+        DCHECK(!m_updatingAnimations);
+        m_updatingAnimations = true;
+    }
+
+    void leaveNoResetAnimationScope();
+
     Persistent<SVGImageChromeClient> m_chromeClient;
     Persistent<Page> m_page;
 
@@ -123,6 +147,9 @@ private:
     // SVGImage. SVGImageForContainer carried the final image size,
     // also called concrete object size.
     IntSize m_intrinsicSize;
+
+    bool m_updatingAnimations;
+    bool m_resetAnimationAfterUpdate;
 };
 
 DEFINE_IMAGE_TYPE_CASTS(SVGImage);