Refactor: Clear m_axObjectCache when AXObject detaches

Source/modules/accessibility/AXProgressIndicator.cpp

Index: Source/modules/accessibility/AXProgressIndicator.cpp
diff --git a/Source/modules/accessibility/AXProgressIndicator.cpp b/Source/modules/accessibility/AXProgressIndicator.cpp
index 8838eebd3a286ee6d6991577c844582dde0d78e4..714bc746ae16ccc004e94fc2403ab2d515657d81 100644
--- a/Source/modules/accessibility/AXProgressIndicator.cpp
+++ b/Source/modules/accessibility/AXProgressIndicator.cpp
@@ -30,12 +30,12 @@ namespace blink {
 
 using namespace HTMLNames;
 
-AXProgressIndicator::AXProgressIndicator(LayoutProgress* layoutObject, AXObjectCacheImpl* axObjectCache)
+AXProgressIndicator::AXProgressIndicator(LayoutProgress* layoutObject, AXObjectCacheImpl& axObjectCache)
     : AXLayoutObject(layoutObject, axObjectCache)
 {
 }
 
-PassRefPtr<AXProgressIndicator> AXProgressIndicator::create(LayoutProgress* layoutObject, AXObjectCacheImpl* axObjectCache)
+PassRefPtr<AXProgressIndicator> AXProgressIndicator::create(LayoutProgress* layoutObject, AXObjectCacheImpl& axObjectCache)
 {
     return adoptRef(new AXProgressIndicator(layoutObject, axObjectCache));
 }