Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXImageMapLink.cpp

Index: Source/modules/accessibility/AXImageMapLink.cpp
diff --git a/Source/modules/accessibility/AXImageMapLink.cpp b/Source/modules/accessibility/AXImageMapLink.cpp
index f8cf6228fbcc54f9998b386520ffaf79dd0d405c..1d26401d4755a2eb79ab61d194e7432ed4608edc 100644
--- a/Source/modules/accessibility/AXImageMapLink.cpp
+++ b/Source/modules/accessibility/AXImageMapLink.cpp
@@ -36,7 +36,7 @@ namespace blink {
 
 using namespace HTMLNames;
 
-AXImageMapLink::AXImageMapLink(AXObjectCacheImpl* axObjectCache)
+AXImageMapLink::AXImageMapLink(AXObjectCacheImpl& axObjectCache)
     : AXMockObject(axObjectCache)
     , m_areaElement(nullptr)
     , m_mapElement(nullptr)
@@ -54,7 +54,7 @@ void AXImageMapLink::detachFromParent()
     m_mapElement = nullptr;
 }
 
-PassRefPtr<AXImageMapLink> AXImageMapLink::create(AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXImageMapLink> AXImageMapLink::create(AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXImageMapLink(axObjectCache));
 }
@@ -67,7 +67,7 @@ AXObject* AXImageMapLink::computeParent() const
     if (!m_mapElement.get() || !m_mapElement->layoutObject())
         return 0;
 
-    return axObjectCache()->getOrCreate(m_mapElement->layoutObject());
+    return axObjectCache().getOrCreate(m_mapElement->layoutObject());
 }
 
 AccessibilityRole AXImageMapLink::roleValue() const