Store SVGElement instead of SVGElementInstance for instancesForElement

Source/core/page/EventHandler.cpp

Index: Source/core/page/EventHandler.cpp
diff --git a/Source/core/page/EventHandler.cpp b/Source/core/page/EventHandler.cpp
index fe0fcb17693312a9b493ac1bc5c384a54ad16bae..f49e71b9a6b850c379b5fbdc7f7d014c2d477e2b 100644
--- a/Source/core/page/EventHandler.cpp
+++ b/Source/core/page/EventHandler.cpp
@@ -85,7 +85,6 @@
 #include "core/rendering/style/CursorList.h"
 #include "core/rendering/style/RenderStyle.h"
 #include "core/svg/SVGDocument.h"
-#include "core/svg/SVGElementInstance.h"
 #include "core/svg/SVGUseElement.h"
 #include "platform/PlatformGestureEvent.h"
 #include "platform/PlatformKeyboardEvent.h"
@@ -260,7 +259,6 @@ void EventHandler::clear()
     m_resizeScrollableArea = 0;
     m_nodeUnderMouse = nullptr;
     m_lastNodeUnderMouse = nullptr;
-    m_lastInstanceUnderMouse = nullptr;
     m_lastMouseMoveEventSubframe = nullptr;
     m_lastScrollbarUnderMouse = nullptr;
     m_clickCount = 0;
@@ -1804,22 +1802,6 @@ MouseEventWithHitTestResults EventHandler::prepareMouseEvent(const HitTestReques
     return m_frame->document()->prepareMouseEvent(request, documentPointForWindowPoint(m_frame, mev.position()), mev);
 }
 
-static inline SVGElementInstance* instanceAssociatedWithShadowTreeElement(Node* referenceNode)
-{
-    if (!referenceNode || !referenceNode->isSVGElement())
-        return 0;
-
-    ShadowRoot* shadowRoot = referenceNode->containingShadowRoot();
-    if (!shadowRoot)
-        return 0;
-
-    Element* shadowTreeParentElement = shadowRoot->host();
-    if (!isSVGUseElement(shadowTreeParentElement))
-        return 0;
-
-    return toSVGUseElement(shadowTreeParentElement)->instanceForShadowTreeElement(referenceNode);
-}
-
 void EventHandler::updateMouseEventTargetNode(Node* targetNode, const PlatformMouseEvent& mouseEvent, bool fireMouseOverOut)
 {
     Node* result = targetNode;
@@ -1834,37 +1816,6 @@ void EventHandler::updateMouseEventTargetNode(Node* targetNode, const PlatformMo
     }
     m_nodeUnderMouse = result;
 
-    // <use> shadow tree elements may have been recloned, update node under mouse in any case
-    if (m_lastInstanceUnderMouse) {
-        SVGElement* lastCorrespondingElement = m_lastInstanceUnderMouse->correspondingElement();
-        SVGElement* lastCorrespondingUseElement = m_lastInstanceUnderMouse->correspondingUseElement();
-
-        if (lastCorrespondingElement && lastCorrespondingUseElement) {
-            HashSet<SVGElementInstance*> instances = lastCorrespondingElement->instancesForElement();
-
-            // Locate the recloned shadow tree element for our corresponding instance
-            HashSet<SVGElementInstance*>::iterator end = instances.end();
-            for (HashSet<SVGElementInstance*>::iterator it = instances.begin(); it != end; ++it) {
-                SVGElementInstance* instance = (*it);
-                ASSERT(instance->correspondingElement() == lastCorrespondingElement);
-
-                if (instance == m_lastInstanceUnderMouse)
-                    continue;
-
-                if (instance->correspondingUseElement() != lastCorrespondingUseElement)
-                    continue;
-
-                SVGElement* shadowTreeElement = instance->shadowTreeElement();
-                if (!shadowTreeElement->inDocument() || m_lastNodeUnderMouse == shadowTreeElement)
-                    continue;
-
-                m_lastNodeUnderMouse = shadowTreeElement;
-                m_lastInstanceUnderMouse = instance;
-                break;
-            }
-        }
-    }
-
     // Fire mouseout/mouseover if the mouse has shifted to a different node.
     if (fireMouseOverOut) {
         RenderLayer* layerForLastNode = layerForNode(m_lastNodeUnderMouse.get());
@@ -1898,7 +1849,6 @@ void EventHandler::updateMouseEventTargetNode(Node* targetNode, const PlatformMo
         if (m_lastNodeUnderMouse && m_lastNodeUnderMouse->document() != m_frame->document()) {
             m_lastNodeUnderMouse = nullptr;
             m_lastScrollbarUnderMouse = nullptr;
-            m_lastInstanceUnderMouse = nullptr;
         }
 
         if (m_lastNodeUnderMouse != m_nodeUnderMouse) {
@@ -1910,7 +1860,6 @@ void EventHandler::updateMouseEventTargetNode(Node* targetNode, const PlatformMo
                 m_nodeUnderMouse->dispatchMouseEvent(mouseEvent, EventTypeNames::mouseover, 0, m_lastNodeUnderMouse.get());
         }
         m_lastNodeUnderMouse = m_nodeUnderMouse;
-        m_lastInstanceUnderMouse = instanceAssociatedWithShadowTreeElement(m_nodeUnderMouse.get());
     }
 }