Reduce how often LayoutSVGShape::updateShapeFromElement is called

Source/core/layout/svg/LayoutSVGShape.cpp

Index: Source/core/layout/svg/LayoutSVGShape.cpp
diff --git a/Source/core/layout/svg/LayoutSVGShape.cpp b/Source/core/layout/svg/LayoutSVGShape.cpp
index f5f47a848267768566bd24f9858ad452e8490d10..26a168391532fb3c186db13a3b5ef6b9f2f733bf 100644
--- a/Source/core/layout/svg/LayoutSVGShape.cpp
+++ b/Source/core/layout/svg/LayoutSVGShape.cpp
@@ -56,19 +56,44 @@ LayoutSVGShape::~LayoutSVGShape()
 {
 }
 
-void LayoutSVGShape::createPath()
+void LayoutSVGShape::styleDidChange(StyleDifference diff, const ComputedStyle* oldStyle)
+{
+    if (diff.needsFullLayout()) {
+        if (oldStyle && (oldStyle->svgStyle().vectorEffect() != style()->svgStyle().vectorEffect()))
+            setNeedsShapeUpdate();
+    }
+
+    // LayoutSVGModelObject will take care of calling clientStyleChanged.
+    LayoutSVGModelObject::styleDidChange(diff, oldStyle);
+}
+
+void LayoutSVGShape::updateShapeFromElement()
 {
     if (!m_path)
         m_path = adoptPtr(new Path());
     *m_path = toSVGGeometryElement(element())->asPath();
 }
 
-void LayoutSVGShape::updateShapeFromElement()
+void LayoutSVGShape::updateStrokeAndFillBoundingBoxes()
 {
-    createPath();
+    m_fillBoundingBox = path().boundingRect();
 
-    m_fillBoundingBox = calculateObjectBoundingBox();
-    m_strokeBoundingBox = calculateStrokeBoundingBox();
+    m_strokeBoundingBox = m_fillBoundingBox;
+    if (style()->svgStyle().hasStroke()) {
+        StrokeData strokeData;
+        SVGLayoutSupport::applyStrokeStyleToStrokeData(strokeData, styleRef(), *this);
+        if (hasNonScalingStroke()) {
+            AffineTransform nonScalingTransform = nonScalingStrokeTransform();
+            if (nonScalingTransform.isInvertible()) {
+                Path* usePath = nonScalingStrokePath(m_path.get(), nonScalingTransform);
+                FloatRect strokeBoundingRect = usePath->strokeBoundingRect(strokeData);
+                strokeBoundingRect = nonScalingTransform.inverse().mapRect(strokeBoundingRect);
+                m_strokeBoundingBox.unite(strokeBoundingRect);
+            }
+        } else {
+            m_strokeBoundingBox.unite(path().strokeBoundingRect(strokeData));
+        }
+    }
 }
 
 FloatRect LayoutSVGShape::hitTestStrokeBoundingBox() const
@@ -152,11 +177,17 @@ void LayoutSVGShape::layout()
     bool updateCachedBoundariesInParents = false;
     LayoutAnalyzer::Scope analyzer(*this);
 
-    if (m_needsShapeUpdate || m_needsBoundariesUpdate) {
+    if (m_needsBoundariesUpdate && toSVGGeometryElement(element())->selfHasRelativeLengths())

[fs, 2015/06/16 10:54:02]

I think this needs to consider the "new" geometric properties ('x', 'y, etc) -
maybe just blanket-compare SVGComputedStyle::layout in
LayoutSVGShape::styleDidChange? (The we'd almost be to drop this bit too -
right?)

[pdr., 2015/06/17 03:50:49]

I think we can just check for the exact property changes we need deeper in
LayoutSVG{Rect,Ellipse}::styleDidChange. I've done this in the latest patchset
and removed this if statement.

+        m_needsShapeUpdate = true;
+
+    if (m_needsShapeUpdate)
         updateShapeFromElement();
-        m_needsShapeUpdate = false;
+
+    if (m_needsBoundariesUpdate || m_needsShapeUpdate) {
+        updateStrokeAndFillBoundingBoxes();
         updatePaintInvalidationBoundingBox();
         m_needsBoundariesUpdate = false;
+        m_needsShapeUpdate = false;
         updateCachedBoundariesInParents = true;
     }
 
@@ -241,35 +272,6 @@ bool LayoutSVGShape::nodeAtFloatPointInternal(const HitTestRequest& request, con
     return false;
 }
 
-FloatRect LayoutSVGShape::calculateObjectBoundingBox() const
-{
-    return path().boundingRect();
-}
-
-FloatRect LayoutSVGShape::calculateStrokeBoundingBox() const
-{
-    ASSERT(m_path);
-    FloatRect strokeBoundingBox = m_fillBoundingBox;
-
-    if (style()->svgStyle().hasStroke()) {
-        StrokeData strokeData;
-        SVGLayoutSupport::applyStrokeStyleToStrokeData(strokeData, styleRef(), *this);
-        if (hasNonScalingStroke()) {
-            AffineTransform nonScalingTransform = nonScalingStrokeTransform();
-            if (nonScalingTransform.isInvertible()) {
-                Path* usePath = nonScalingStrokePath(m_path.get(), nonScalingTransform);
-                FloatRect strokeBoundingRect = usePath->strokeBoundingRect(strokeData);
-                strokeBoundingRect = nonScalingTransform.inverse().mapRect(strokeBoundingRect);
-                strokeBoundingBox.unite(strokeBoundingRect);
-            }
-        } else {
-            strokeBoundingBox.unite(path().strokeBoundingRect(strokeData));
-        }
-    }
-
-    return strokeBoundingBox;
-}
-
 void LayoutSVGShape::updatePaintInvalidationBoundingBox()
 {
     m_paintInvalidationBoundingBox = strokeBoundingBox();