Backed out changeset be654bd9e20d (bug 1131801)

dom/html/nsHTMLDocument.cpp

@@ -1664,6 +1664,12 @@ nsHTMLDocument::Open(JSContext* cx,
           }
         }
       }
+
+      nsIXPConnect *xpc = nsContentUtils::XPConnect();
+      rv = xpc->RescueOrphansInScope(cx, oldScope->GetGlobalJSObject());
+      if (rv.Failed()) {
+        return nullptr;
+      }
     }
   }
 

js/xpconnect/idl/nsIXPConnect.idl

@@ -267,7 +267,7 @@ interface nsIXPCFunctionThisTranslator : nsISupports
     { 0xbd, 0xd6, 0x0, 0x0, 0x64, 0x65, 0x73, 0x74 } }
 %}
 
-[noscript, uuid(6872bfd6-660b-4aa3-b54b-41ce1d2d69e3)]
+[noscript, uuid(75975244-2cf0-43b1-b79a-9fd447fac06b)]
 interface nsIXPConnect : nsISupports
 {
 %{ C++
@@ -465,6 +465,9 @@ interface nsIXPConnect : nsISupports
     setFunctionThisTranslator(in nsIIDRef aIID,
                               in nsIXPCFunctionThisTranslator aTranslator);
 
+    void
+    rescueOrphansInScope(in JSContextPtr aJSContext, in JSObjectPtr  aScope);
+
     nsIXPConnectJSObjectHolder
     getWrappedNativePrototype(in JSContextPtr aJSContext,
                               in JSObjectPtr  aScope,

js/xpconnect/src/nsXPConnect.cpp

@@ -690,6 +690,42 @@ nsXPConnect::GetWrappedNativeOfNativeObject(JSContext * aJSContext,
     return NS_OK;
 }
 
+static PLDHashOperator
+MoveableWrapperFinder(PLDHashTable *table, PLDHashEntryHdr *hdr,
+                      uint32_t number, void *arg)
+{
+    nsTArray<nsRefPtr<XPCWrappedNative> > *array =
+        static_cast<nsTArray<nsRefPtr<XPCWrappedNative> > *>(arg);
+    XPCWrappedNative *wn = ((Native2WrappedNativeMap::Entry*)hdr)->value;
+
+    // If a wrapper is expired, then there are no references to it from JS, so
+    // we don't have to move it.
+    if (!wn->IsWrapperExpired())
+        array->AppendElement(wn);
+    return PL_DHASH_NEXT;
+}
+
+/* void rescueOrphansInScope(in JSContextPtr aJSContext, in JSObjectPtr  aScope); */
+NS_IMETHODIMP
+nsXPConnect::RescueOrphansInScope(JSContext *aJSContext, JSObject *aScopeArg)
+{
+    RootedObject aScope(aJSContext, aScopeArg);
+
+    XPCWrappedNativeScope *scope = ObjectScope(aScope);
+    if (!scope)
+        return UnexpectedFailure(NS_ERROR_FAILURE);
+
+    // First, look through the old scope and find all of the wrappers that we
+    // might need to rescue.
+    nsTArray<nsRefPtr<XPCWrappedNative> > wrappersToMove;
+
+    Native2WrappedNativeMap *map = scope->GetWrappedNativeMap();
+    wrappersToMove.SetCapacity(map->Count());
+    map->Enumerate(MoveableWrapperFinder, &wrappersToMove);
+
+    return NS_OK;
+}
+
 /* nsIStackFrame createStackFrameLocation (in uint32_t aLanguage, in string aFilename, in string aFunctionName, in int32_t aLineNumber, in nsIStackFrame aCaller); */
 NS_IMETHODIMP
 nsXPConnect::CreateStackFrameLocation(uint32_t aLanguage,