coverity#1371262 Missing move assignment operator

Change-Id: Ibb430a683f818add50facc23ac2893b558bff70c

include/svx/AccessibleShapeTreeInfo.hxx

@@ -66,6 +66,8 @@ public:
 
     AccessibleShapeTreeInfo& operator= (const AccessibleShapeTreeInfo& rInfo);
 
+    void dispose();
+
     /** Deprecated.  Don't use this method.
     */
     void SetDocumentWindow (const css::uno::Reference<

svx/source/accessibility/AccessibleShape.cxx

@@ -1264,7 +1264,7 @@ void AccessibleShape::disposing()
     // Cleanup.  Remove references to objects to allow them to be
     // destroyed.
     mxShape = nullptr;
-    maShapeTreeInfo = AccessibleShapeTreeInfo();
+    maShapeTreeInfo.dispose();
 
     // Call base classes.
     AccessibleContextBase::dispose ();

svx/source/accessibility/AccessibleShapeTreeInfo.cxx

@@ -48,6 +48,15 @@ AccessibleShapeTreeInfo::AccessibleShapeTreeInfo (const AccessibleShapeTreeInfo&
     // Empty.
 }
 
+void AccessibleShapeTreeInfo::dispose()
+{
+    mxDocumentWindow.clear();
+    mxModelBroadcaster.clear();
+    mpView = nullptr;
+    mxController.clear();
+    mpWindow.reset();
+    mpViewForwarder = nullptr;
+}
 
 AccessibleShapeTreeInfo& AccessibleShapeTreeInfo::operator= (const AccessibleShapeTreeInfo& rInfo)
 {

svx/source/table/accessiblecell.cxx

@@ -528,7 +528,7 @@ void AccessibleCell::disposing()
     // Cleanup.  Remove references to objects to allow them to be
     // destroyed.
     mxCell.clear();
-    maShapeTreeInfo = AccessibleShapeTreeInfo();
+    maShapeTreeInfo.dispose();
 
     // Call base classes.
     AccessibleContextBase::dispose ();