diff --git a/dom/public/base/nsPIDOMWindow.h b/dom/public/base/nsPIDOMWindow.h
index 9fd139c5f574..9c73fa4379aa 100644
--- a/dom/public/base/nsPIDOMWindow.h
+++ b/dom/public/base/nsPIDOMWindow.h
@@ -77,8 +77,8 @@ class nsIDocument;
 struct nsTimeout;
 
 #define NS_PIDOMWINDOW_IID \
-{ 0x207fe64a, 0x7123, 0x43d0, \
-  { 0x91, 0x1d, 0x51, 0x19, 0x35, 0x9a, 0xb5, 0x77 } }
+{ 0xabb217ba, 0x2528, 0x467e, \
+ { 0xaa, 0x29, 0xdd, 0x84, 0x2d, 0x97, 0x3c, 0x78 } }
 
 class nsPIDOMWindow : public nsIDOMWindowInternal
 {
@@ -280,6 +280,15 @@ public:
     return mInnerWindow;
   }
 
+  nsPIDOMWindow *EnsureInnerWindow()
+  {
+    NS_ASSERTION(IsOuterWindow(), "EnsureInnerWindow called on inner window");
+    // GetDocument forces inner window creation if there isn't one already
+    nsCOMPtr<nsIDOMDocument> doc;
+    GetDocument(getter_AddRefs(doc));
+    return GetCurrentInnerWindow();
+  }
+
   PRBool IsInnerWindow() const
   {
     return mIsInnerWindow;
diff --git a/dom/src/base/nsDOMClassInfo.cpp b/dom/src/base/nsDOMClassInfo.cpp
index 9e3785016a3c..c6a5b600fc93 100644
--- a/dom/src/base/nsDOMClassInfo.cpp
+++ b/dom/src/base/nsDOMClassInfo.cpp
@@ -5627,22 +5627,18 @@ nsWindowSH::NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
       // We're resolving a property on an outer window for which there
       // is no inner window yet, and the window is not frozen
       // (i.e. we're not in the middle of initializing XPConnect
-      // classes on it). If the context is already initalized, trigger
-      // creation of a new inner window by calling GetDocument() on
-      // the outer window. This will create a synthetic about:blank
-      // document, and an inner window which may be reused by the
-      // actual document being loaded into this outer window. This way
-      // properties defined on the window before the document load
-      // started will be visible to the document once it's loaded,
-      // assuming same origin etc.
+      // classes on it). If the context is already initalized, force
+      // creation of a new inner window. This will create a synthetic
+      // about:blank document, and an inner window which may be reused
+      // by the actual document being loaded into this outer
+      // window. This way properties defined on the window before the
+      // document load started will be visible to the document once
+      // it's loaded, assuming same origin etc.
       nsIScriptContext *scx = win->GetContextInternal();
 
       if (scx && scx->IsContextInitialized()) {
-        nsCOMPtr<nsIDOMDocument> doc;
-        win->GetDocument(getter_AddRefs(doc));
-
         // Grab the new inner window.
-        innerWin = win->GetCurrentInnerWindowInternal();
+        innerWin = win->EnsureInnerWindowInternal();
 
         if (!innerWin) {
           return NS_ERROR_OUT_OF_MEMORY;
diff --git a/dom/src/base/nsGlobalWindow.h b/dom/src/base/nsGlobalWindow.h
index 7451617e282e..2e8c34d9ed36 100644
--- a/dom/src/base/nsGlobalWindow.h
+++ b/dom/src/base/nsGlobalWindow.h
@@ -266,6 +266,11 @@ public:
     return NS_STATIC_CAST(nsGlobalWindow *, mInnerWindow);
   }
 
+  nsGlobalWindow *EnsureInnerWindowInternal()
+  {
+    return NS_STATIC_CAST(nsGlobalWindow *, EnsureInnerWindow());
+  }
+
   PRBool IsFrozen() const
   {
     return mIsFrozen;
diff --git a/dom/src/jsurl/nsJSProtocolHandler.cpp b/dom/src/jsurl/nsJSProtocolHandler.cpp
index a16e943fdfeb..89abf76461ed 100644
--- a/dom/src/jsurl/nsJSProtocolHandler.cpp
+++ b/dom/src/jsurl/nsJSProtocolHandler.cpp
@@ -150,12 +150,9 @@ nsresult nsJSThunk::EvaluateScript(nsIChannel *aChannel)
 
     nsCOMPtr<nsPIDOMWindow> win(do_QueryInterface(global));
 
-    // Get the document out of the window to make sure we create a new
-    // inner window if one doesn't already exist (see bug 306630).
-    nsCOMPtr<nsIDOMDocument> doc;
-    win->GetDocument(getter_AddRefs(doc));
-
-    nsPIDOMWindow *innerWin = win->GetCurrentInnerWindow();
+    // Make sure we create a new inner window if one doesn't already exist (see
+    // bug 306630).
+    nsPIDOMWindow *innerWin = win->EnsureInnerWindow();
 
     if (!innerWin) {
         return NS_ERROR_UNEXPECTED;
@@ -178,15 +175,6 @@ nsresult nsJSThunk::EvaluateScript(nsIChannel *aChannel)
         return NS_ERROR_DOM_RETVAL_UNDEFINED;
     }
 
-    // Now get the DOM Document.  Accessing the document will create one
-    // if necessary.  So, basically, this call ensures that a document gets
-    // created -- if necessary.
-    rv = domWindow->GetDocument(getter_AddRefs(doc));
-    NS_ASSERTION(doc, "No DOMDocument!");
-    if (NS_FAILED(rv)) {
-        return NS_ERROR_FAILURE;
-    }
-
     nsCOMPtr<nsIScriptContext> scriptContext = global->GetContext();
     if (!scriptContext)
         return NS_ERROR_FAILURE;