Gecko vbuf backend: Remove old workaround for old versions of Firefox…

… which didn't fire reorder on iframes. (#10174)

In Firefox <= 3.5, a reorder event wasn't fired on an iframe when its embedded document changed (Mozilla bug 420845).
To work around this, the Gecko vbuf had code in its win event callback to retrieve the target for stateChange events and query the NODE_CHILD_OF relation to get the iframe.
This was fixed in Firefox 3.6 (10 years ago) and thus is no longer needed.
Also, this code causes us to retrieve objects unnecessarily in the win event callback, which does matter more in Firefox now that these are cross-process calls.
Although I wouldn't have thought this would have much of a performance impact, this code path does show up in Firefox profiling.

nvdaHelper/vbufBackends/gecko_ia2/gecko_ia2.cpp

@@ -61,7 +61,6 @@ CComPtr<IAccessible2> GeckoVBufBackend_t::getLabelElement(IAccessible2_2* elemen
 }
 
 #define NAVRELATION_LABELLED_BY 0x1003
-#define NAVRELATION_NODE_CHILD_OF 0x1005
 const wchar_t EMBEDDED_OBJ_CHAR = 0xFFFC;
 
 HWND findRealMozillaWindow(HWND hwnd) {
@@ -1042,59 +1041,6 @@ VBufStorage_fieldNode_t* GeckoVBufBackend_t::fillVBuf(IAccessible2* pacc,
 	return parentNode;
 }
 
-bool getDocumentFrame(HWND* hwnd, long* childID) {
-	IAccessible2* pacc=IAccessible2FromIdentifier(HandleToUlong(*hwnd),*childID);
-	if (!pacc)
-		return false;
-
-	IAccessible2* parentPacc=NULL;
-	VARIANT varChild;
-	varChild.vt=VT_I4;
-	varChild.lVal=*childID;
-	VARIANT varDisp;
-	if(pacc->accNavigate(NAVRELATION_NODE_CHILD_OF,varChild,&varDisp)!=S_OK) {
-		pacc->Release();
-		return false;
-	}
-	pacc->Release();
-
-	if(varDisp.vt!=VT_DISPATCH) {
-		VariantClear(&varDisp);
-		return false;
-	}
-
-	if(varDisp.pdispVal->QueryInterface(IID_IAccessible2,(void**)&parentPacc)!=S_OK) {
-		VariantClear(&varDisp);
-		return false;
-	}
-	VariantClear(&varDisp);
-
-	if(parentPacc==pacc) {
-		parentPacc->Release();
-		return false;
-	}
-
-	long role;
-	if(parentPacc->role(&role)!=S_OK||role!=IA2_ROLE_INTERNAL_FRAME) {
-		parentPacc->Release();
-		return false;
-	}
-
-	if(parentPacc->get_uniqueID(childID)!=S_OK||*childID>=0) {
-		parentPacc->Release();
-		return false;
-	}
-
-	if(parentPacc->get_windowHandle(hwnd)!=S_OK) {
-		parentPacc->Release();
-		return false;
-	}
-
-	parentPacc->Release();
-
-	return true;
-}
-
 void CALLBACK GeckoVBufBackend_t::renderThread_winEventProcHook(HWINEVENTHOOK hookID, DWORD eventID, HWND hwnd, long objectID, long childID, DWORD threadID, DWORD time) {
 	switch(eventID) {
 		case EVENT_OBJECT_FOCUS:
@@ -1145,20 +1091,6 @@ void CALLBACK GeckoVBufBackend_t::renderThread_winEventProcHook(HWINEVENTHOOK ho
 			return;
 
 		VBufStorage_controlFieldNode_t* node=backend->getControlFieldNodeWithIdentifier(docHandle,ID);
-		if(!node&&eventID==EVENT_OBJECT_STATECHANGE) {
-			// This event is possibly due to a new document loading in a subframe.
-			// Gecko doesn't fire a reorder on the iframe (Mozilla bug 420845), so we need to use NODE_CHILD_OF in this case so that frames will reload.
-			LOG_DEBUG(L"State change on an unknown node in a subframe, try NODE_CHILD_OF");
-			if (getDocumentFrame(&hwnd, &childID)) {
-				#ifdef DEBUG
-				Beep(2000,50);
-				#endif
-				LOG_DEBUG(L"Got NODE_CHILD_OF, recursing");
-				renderThread_winEventProcHook(hookID,eventID,hwnd,OBJID_CLIENT,childID,threadID,time);
-			} else
-				LOG_DEBUG(L"NODE_CHILD_OF failed, returning");
-			continue;
-		}
 		if(!node)
 			continue;
 		backend->invalidateSubtree(node);