Common up SVG transform "change detection" (classification)

third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp

Index: third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp b/third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp
index 3c7b70ca1ad1194c04ae01d532c56181c2212d12..44fda47e55e25b2c686821b5e80ec34b3ec35c20 100644
--- a/third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/LayoutSVGTransformableContainer.cpp
@@ -72,12 +72,7 @@ void LayoutSVGTransformableContainer::setNeedsTransformUpdate()
     m_needsTransformUpdate = true;
 }
 
-static std::pair<double, double> scaleReference(const AffineTransform& transform)
-{
-    return std::make_pair(transform.xScaleSquared(), transform.yScaleSquared());
-}
-
-LayoutSVGContainer::TransformChange LayoutSVGTransformableContainer::calculateLocalTransform()
+SVGTransformChange LayoutSVGTransformableContainer::calculateLocalTransform()
 {
     SVGGraphicsElement* element = toSVGGraphicsElement(this->element());
     ASSERT(element);
@@ -108,14 +103,13 @@ LayoutSVGContainer::TransformChange LayoutSVGTransformableContainer::calculateLo
     }
 
     if (!m_needsTransformUpdate)
-        return TransformChange::None;
+        return SVGTransformChange::None;
 
-    std::pair<double, double> oldScale = scaleReference(m_localTransform);
+    SVGTransformChangeDetector changeDetector(m_localTransform);
     m_localTransform = element->calculateAnimatedLocalTransform();
     m_localTransform.translate(m_additionalTranslation.width(), m_additionalTranslation.height());
     m_needsTransformUpdate = false;
-    return scaleReference(m_localTransform) != oldScale
-        ? TransformChange::Full : TransformChange::ScaleInvariant;
+    return changeDetector.computeChange(m_localTransform);
 }
 
 } // namespace blink