Lazily allocate svg shape transforms, shrink RenderSVGShape by 44B

This patch switches to lazily allocating transforms in RenderSVGShape
because local transforms are relatively rare.

BUG=429551

Review URL: https://codereview.chromium.org/701433002

git-svn-id: svn://svn.chromium.org/blink/trunk@185118 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/rendering/svg/RenderSVGShape.cpp

@@ -110,6 +110,19 @@ bool RenderSVGShape::strokeContains(const FloatPoint& point, bool requiresStroke
     return shapeDependentStrokeContains(point);
 }
 
+void RenderSVGShape::updateLocalTransform()
+{
+    SVGGraphicsElement* graphicsElement = toSVGGraphicsElement(element());
+    if (graphicsElement->hasAnimatedLocalTransform()) {
+        if (m_localTransform)
+            m_localTransform->setTransform(graphicsElement->calculateAnimatedLocalTransform());
+        else
+            m_localTransform = adoptPtr(new AffineTransform(graphicsElement->calculateAnimatedLocalTransform()));
+    } else {
+        m_localTransform = 0;
+    }
+}
+
 void RenderSVGShape::layout()
 {
     bool updateCachedBoundariesInParents = false;
@@ -123,7 +136,7 @@ void RenderSVGShape::layout()
     }
 
     if (m_needsTransformUpdate) {
-        m_localTransform =  toSVGGraphicsElement(element())->calculateAnimatedLocalTransform();
+        updateLocalTransform();
         m_needsTransformUpdate = false;
         updateCachedBoundariesInParents = true;
     }
@@ -175,7 +188,7 @@ bool RenderSVGShape::nodeAtFloatPoint(const HitTestRequest& request, HitTestResu
         return false;
 
     FloatPoint localPoint;
-    if (!SVGRenderSupport::transformToUserSpaceAndCheckClipping(this, m_localTransform, pointInParent, localPoint))
+    if (!SVGRenderSupport::transformToUserSpaceAndCheckClipping(this, localToParentTransform(), pointInParent, localPoint))
         return false;
 
     PointerEventsHitRules hitRules(PointerEventsHitRules::SVG_GEOMETRY_HITTESTING, request, style()->pointerEvents());

third_party/WebKit/Source/core/rendering/svg/RenderSVGShape.h

@@ -70,7 +70,7 @@ public:
     bool hasNonScalingStroke() const { return style()->svgStyle().vectorEffect() == VE_NON_SCALING_STROKE; }
     Path* nonScalingStrokePath(const Path*, const AffineTransform&) const;
     AffineTransform nonScalingStrokeTransform() const;
-    virtual AffineTransform localTransform() const override final { return m_localTransform; }
+    virtual AffineTransform localTransform() const override final { return m_localTransform ? *m_localTransform : RenderSVGModelObject::localTransform(); }
 
     virtual const Vector<MarkerPosition>* markerPositions() const { return 0; }
 
@@ -98,7 +98,7 @@ private:
     bool fillContains(const FloatPoint&, bool requiresFill = true, const WindRule fillRule = RULE_NONZERO);
     bool strokeContains(const FloatPoint&, bool requiresStroke = true);
 
-    virtual const AffineTransform& localToParentTransform() const override final { return m_localTransform; }
+    virtual const AffineTransform& localToParentTransform() const override final { return m_localTransform ? *m_localTransform : RenderSVGModelObject::localToParentTransform(); }
 
     virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectSVGShape || RenderSVGModelObject::isOfType(type); }
     virtual const char* renderName() const override { return "RenderSVGShape"; }
@@ -113,10 +113,11 @@ private:
     FloatRect calculateObjectBoundingBox() const;
     FloatRect calculateStrokeBoundingBox() const;
     void updatePaintInvalidationBoundingBox();
+    void updateLocalTransform();
 
 private:
     FloatRect m_paintInvalidationBoundingBox;
-    AffineTransform m_localTransform;
+    OwnPtr<AffineTransform> m_localTransform;
     OwnPtr<Path> m_path;
 
     bool m_needsBoundariesUpdate : 1;

third_party/WebKit/Source/core/svg/SVGGraphicsElement.cpp

@@ -122,6 +122,14 @@ PassRefPtr<SVGMatrixTearOff> SVGGraphicsElement::getScreenCTMFromJavascript()
     return SVGMatrixTearOff::create(getScreenCTM());
 }
 
+bool SVGGraphicsElement::hasAnimatedLocalTransform() const
+{
+    RenderStyle* style = renderer() ? renderer()->style() : 0;
+
+    // Each of these is used in SVGGraphicsElement::calculateAnimatedLocalTransform to create an animated local transform.
+    return (style && style->hasTransform()) || !m_transform->currentValue()->isEmpty() || hasSVGRareData();
+}
+
 AffineTransform SVGGraphicsElement::calculateAnimatedLocalTransform() const
 {
     AffineTransform matrix;

third_party/WebKit/Source/core/svg/SVGGraphicsElement.h

@@ -51,6 +51,7 @@ public:
     SVGElement* farthestViewportElement() const;
 
     virtual AffineTransform localCoordinateSpaceTransform(SVGElement::CTMScope) const override { return calculateAnimatedLocalTransform(); }
+    bool hasAnimatedLocalTransform() const;
     AffineTransform calculateAnimatedLocalTransform() const;
     virtual AffineTransform* animateMotionTransform() override;
 

third_party/WebKit/Source/platform/transforms/AffineTransform.h

@@ -51,6 +51,8 @@ public:
 
     void setMatrix(double a, double b, double c, double d, double e, double f);
 
+    void setTransform(const AffineTransform& other) { setMatrix(other.m_transform); }
+
     void map(double x, double y, double& x2, double& y2) const;
 
     // Rounds the mapped point to the nearest integer value.