diff --git a/content/xbl/src/nsXBLDocumentInfo.cpp b/content/xbl/src/nsXBLDocumentInfo.cpp
index f36bae125e6..7126fcf4b24 100644
--- a/content/xbl/src/nsXBLDocumentInfo.cpp
+++ b/content/xbl/src/nsXBLDocumentInfo.cpp
@@ -76,6 +76,7 @@ public:
   virtual JSObject *GetGlobalJSObject();
   virtual void OnFinalize(PRUint32 aLangID, void *aScriptGlobal);
   virtual void SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts);
+  virtual nsresult SetNewArguments(nsIArray *aArguments);
 
   // nsIScriptObjectPrincipal methods
   virtual nsIPrincipal* GetPrincipal();
@@ -392,6 +393,13 @@ nsXBLDocGlobalObject::SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts)
     // We don't care...
 }
 
+nsresult
+nsXBLDocGlobalObject::SetNewArguments(nsIArray *aArguments)
+{
+  NS_NOTREACHED("waaah!");
+  return NS_ERROR_UNEXPECTED;
+}
+
 //----------------------------------------------------------------------
 //
 // nsIScriptObjectPrincipal methods
diff --git a/content/xul/document/src/nsXULPrototypeDocument.cpp b/content/xul/document/src/nsXULPrototypeDocument.cpp
index e0aa6703033..394cad57f61 100644
--- a/content/xul/document/src/nsXULPrototypeDocument.cpp
+++ b/content/xul/document/src/nsXULPrototypeDocument.cpp
@@ -81,6 +81,7 @@ public:
     // nsIScriptGlobalObject methods
     virtual void OnFinalize(PRUint32 aLangID, void *aGlobal);
     virtual void SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts);
+    virtual nsresult SetNewArguments(nsIArray *aArguments);
 
     virtual void *GetScriptGlobal(PRUint32 lang);
     virtual nsresult EnsureScriptEnvironment(PRUint32 aLangID);
@@ -808,6 +809,13 @@ nsXULPDGlobalObject::SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts)
     // We don't care...
 }
 
+nsresult
+nsXULPDGlobalObject::SetNewArguments(nsIArray *aArguments)
+{
+    NS_NOTREACHED("waaah!");
+    return NS_ERROR_UNEXPECTED;
+}
+
 //----------------------------------------------------------------------
 //
 // nsIScriptObjectPrincipal methods
diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index 45293fe29c6..e515a3b6229 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -1376,7 +1376,6 @@ jsval nsDOMClassInfo::sToolbar_id         = JSVAL_VOID;
 jsval nsDOMClassInfo::sLocationbar_id     = JSVAL_VOID;
 jsval nsDOMClassInfo::sPersonalbar_id     = JSVAL_VOID;
 jsval nsDOMClassInfo::sStatusbar_id       = JSVAL_VOID;
-jsval nsDOMClassInfo::sDialogArguments_id = JSVAL_VOID;
 jsval nsDOMClassInfo::sDirectories_id     = JSVAL_VOID;
 jsval nsDOMClassInfo::sControllers_id     = JSVAL_VOID;
 jsval nsDOMClassInfo::sLength_id          = JSVAL_VOID;
@@ -1572,7 +1571,6 @@ nsDOMClassInfo::DefineStaticJSVals(JSContext *cx)
   SET_JSVAL_TO_STRING(sLocationbar_id,     cx, "locationbar");
   SET_JSVAL_TO_STRING(sPersonalbar_id,     cx, "personalbar");
   SET_JSVAL_TO_STRING(sStatusbar_id,       cx, "statusbar");
-  SET_JSVAL_TO_STRING(sDialogArguments_id, cx, "dialogArguments");
   SET_JSVAL_TO_STRING(sDirectories_id,     cx, "directories");
   SET_JSVAL_TO_STRING(sControllers_id,     cx, "controllers");
   SET_JSVAL_TO_STRING(sLength_id,          cx, "length");
@@ -4324,7 +4322,6 @@ nsDOMClassInfo::ShutDown()
   sLocationbar_id     = JSVAL_VOID;
   sPersonalbar_id     = JSVAL_VOID;
   sStatusbar_id       = JSVAL_VOID;
-  sDialogArguments_id = JSVAL_VOID;
   sDirectories_id     = JSVAL_VOID;
   sControllers_id     = JSVAL_VOID;
   sLength_id          = JSVAL_VOID;
@@ -6558,24 +6555,6 @@ nsWindowSH::NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
           return NS_OK;
         }
       }
-    } else if (id == sDialogArguments_id &&
-               mData == &sClassInfoData[eDOMClassInfo_ModalContentWindow_id]) {
-      nsCOMPtr<nsIArray> args;
-      ((nsGlobalModalWindow *)win)->GetDialogArguments(getter_AddRefs(args));
-
-      nsIScriptContext *script_cx = win->GetContext();
-      if (script_cx) {
-        JSAutoSuspendRequest asr(cx);
-
-        // Make nsJSContext::SetProperty()'s magic argument array
-        // handling happen.
-        rv = script_cx->SetProperty(obj, "dialogArguments", args);
-        NS_ENSURE_SUCCESS(rv, rv);
-
-        *objp = obj;
-      }
-
-      return NS_OK;
     }
   }
 
@@ -6592,7 +6571,8 @@ nsWindowSH::NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
   // binding a name) a new undefined property that's not already
   // defined on our prototype chain. This way we can access this
   // expando w/o ever getting back into XPConnect.
-  if ((flags & JSRESOLVE_ASSIGNING) && !(flags & JSRESOLVE_WITH) &&
+  if ((flags & JSRESOLVE_ASSIGNING) &&
+      !(flags & JSRESOLVE_WITH) &&
       win->IsInnerWindow()) {
     JSObject *realObj;
     wrapper->GetJSObject(&realObj);
@@ -9494,10 +9474,7 @@ nsHTMLPluginObjElementSH::PostCreate(nsIXPConnectWrappedNative *wrapper,
                                      JSContext *cx, JSObject *obj)
 {
   if (nsContentUtils::IsSafeToRunScript()) {
-#ifdef DEBUG
-    nsresult rv =
-#endif
-      SetupProtoChain(wrapper, cx, obj);
+    nsresult rv = SetupProtoChain(wrapper, cx, obj);
 
     // If SetupProtoChain failed then we're in real trouble. We're about to fail
     // PostCreate but it's more than likely that we handed our (now invalid)
diff --git a/dom/base/nsDOMClassInfo.h b/dom/base/nsDOMClassInfo.h
index 1b326cd8aa9..bf9fc317831 100644
--- a/dom/base/nsDOMClassInfo.h
+++ b/dom/base/nsDOMClassInfo.h
@@ -284,7 +284,6 @@ protected:
   static jsval sLocationbar_id;
   static jsval sPersonalbar_id;
   static jsval sStatusbar_id;
-  static jsval sDialogArguments_id;
   static jsval sDirectories_id;
   static jsval sControllers_id;
   static jsval sLength_id;
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index dd28a792412..8034d7371a0 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -895,7 +895,6 @@ nsGlobalWindow::CleanUp()
   }
   mArguments = nsnull;
   mArgumentsLast = nsnull;
-  mArgumentsOrigin = nsnull;
 
   CleanupCachedXBLHandlers(this);
 
@@ -1195,7 +1194,7 @@ nsGlobalWindow::SetScriptContext(PRUint32 lang_id, nsIScriptContext *aScriptCont
     NS_ASSERTION(script_glob, "GetNativeGlobal returned NULL!");
   }
   // for now, keep mContext real.
-  if (lang_id == nsIProgrammingLanguage::JAVASCRIPT) {
+  if (lang_id==nsIProgrammingLanguage::JAVASCRIPT) {
     mContext = aScriptContext;
     mJSObject = (JSObject *)script_glob;
   }
@@ -2025,12 +2024,8 @@ nsGlobalWindow::SetNewDocument(nsIDocument* aDocument,
       }
 
       if (mArguments) {
-        newInnerWindow->DefineArgumentsProperty(mArguments);
-        newInnerWindow->mArguments = mArguments;
-        newInnerWindow->mArgumentsOrigin = mArgumentsOrigin;
-
+        newInnerWindow->SetNewArguments(mArguments);
         mArguments = nsnull;
-        mArgumentsOrigin = nsnull;
       }
 
       // Give the new inner window our chrome event handler (since it
@@ -2114,10 +2109,9 @@ nsGlobalWindow::SetDocShell(nsIDocShell* aDocShell)
 
     if (mArguments) { 
       // We got no new document after someone called
-      // SetArguments(), drop our reference to the arguments.
+      // SetNewArguments(), drop our reference to the arguments.
       mArguments = nsnull;
-      mArgumentsLast = nsnull;
-      mArgumentsOrigin = nsnull;
+      // xxxmarkh - should we also drop mArgumentsLast?
     }
 
     PRUint32 st_ndx;
@@ -2370,52 +2364,41 @@ nsGlobalWindow::SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts)
 }
 
 nsresult
-nsGlobalWindow::SetArguments(nsIArray *aArguments, nsIPrincipal *aOrigin)
+nsGlobalWindow::SetNewArguments(nsIArray *aArguments)
 {
-  FORWARD_TO_OUTER(SetArguments, (aArguments, aOrigin),
-                   NS_ERROR_NOT_INITIALIZED);
+  FORWARD_TO_OUTER(SetNewArguments, (aArguments), NS_ERROR_NOT_INITIALIZED);
+
+  JSContext *cx;
+  NS_ENSURE_TRUE(aArguments && mContext &&
+                 (cx = (JSContext *)mContext->GetNativeContext()),
+                 NS_ERROR_NOT_INITIALIZED);
+
+  // Note that currentInner may be non-null if someone's doing a
+  // window.open with an existing window name.
+  nsGlobalWindow *currentInner = GetCurrentInnerWindowInternal();
+  
+  nsresult rv;
+
+  if (currentInner) {
+    PRUint32 langID;
+    NS_STID_FOR_ID(langID) {
+      void *glob = currentInner->GetScriptGlobal(langID);
+      nsIScriptContext *ctx = GetScriptContext(langID);
+      if (glob && ctx) {
+        if (mIsModalContentWindow) {
+          rv = ctx->SetProperty(glob, "dialogArguments", aArguments);
+        } else {
+          rv = ctx->SetProperty(glob, "arguments", aArguments);
+        }
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+    }
+  }
 
   // Hold on to the arguments so that we can re-set them once the next
   // document is loaded.
   mArguments = aArguments;
-  mArgumentsOrigin = aOrigin;
-
-  if (!mIsModalContentWindow) {
-    mArgumentsLast = aArguments;
-  }
-
-  nsGlobalWindow *currentInner = GetCurrentInnerWindowInternal();
-
-  return currentInner ?
-    currentInner->DefineArgumentsProperty(aArguments) : NS_OK;
-}
-
-nsresult
-nsGlobalWindow::DefineArgumentsProperty(nsIArray *aArguments)
-{
-  JSContext *cx;
-  nsIScriptContext *ctx = GetOuterWindowInternal()->mContext;
-  NS_ENSURE_TRUE(aArguments && ctx &&
-                 (cx = (JSContext *)ctx->GetNativeContext()),
-                 NS_ERROR_NOT_INITIALIZED);
-
-  if (mIsModalContentWindow) {
-    // Modal content windows don't have an "arguments" property, they
-    // have a "dialogArguments" property which is handled
-    // separately. See nsWindowSH::NewResolve().
-
-    return NS_OK;
-  }
-
-  PRUint32 langID;
-  NS_STID_FOR_ID(langID) {
-    void *glob = GetScriptGlobal(langID);
-    ctx = GetScriptContext(langID);
-    if (glob && ctx) {
-      nsresult rv = ctx->SetProperty(glob, "arguments", aArguments);
-      NS_ENSURE_SUCCESS(rv, rv);
-    }
-  }
+  mArgumentsLast = aArguments;
 
   return NS_OK;
 }
@@ -6104,42 +6087,14 @@ nsGlobalWindow::ShowModalDialog(const nsAString& aURI, nsIVariant *aArgs,
   NS_ENSURE_SUCCESS(rv, rv);
   
   if (dlgWin) {
-    nsCOMPtr<nsIPrincipal> subjectPrincipal;
-    rv = nsContentUtils::GetSecurityManager()->
-      GetSubjectPrincipal(getter_AddRefs(subjectPrincipal));
-    if (NS_FAILED(rv)) {
-      return rv;
-    }
+    nsCOMPtr<nsPIDOMWindow> win(do_QueryInterface(dlgWin));
 
-    PRBool canAccess = PR_TRUE;
+    nsPIDOMWindow *inner = win->GetCurrentInnerWindow();
 
-    if (subjectPrincipal) {
-      nsCOMPtr<nsIScriptObjectPrincipal> objPrincipal =
-        do_QueryInterface(dlgWin);
-      nsCOMPtr<nsIPrincipal> dialogPrincipal;
+    nsCOMPtr<nsIDOMModalContentWindow> dlgInner(do_QueryInterface(inner));
 
-      if (objPrincipal) {
-        dialogPrincipal = objPrincipal->GetPrincipal();
-
-        rv = subjectPrincipal->Subsumes(dialogPrincipal, &canAccess);
-        NS_ENSURE_SUCCESS(rv, rv);
-      } else {
-        // Uh, not sure what kind of dialog this is. Prevent access to
-        // be on the safe side...
-
-        canAccess = PR_FALSE;
-      }
-    }
-
-    if (canAccess) {
-      nsCOMPtr<nsPIDOMWindow> win(do_QueryInterface(dlgWin));
-      nsPIDOMWindow *inner = win->GetCurrentInnerWindow();
-
-      nsCOMPtr<nsIDOMModalContentWindow> dlgInner(do_QueryInterface(inner));
-
-      if (dlgInner) {
-        dlgInner->GetReturnValue(aRetVal);
-      }
+    if (dlgInner) {
+      dlgInner->GetReturnValue(aRetVal);
     }
   }
   
@@ -7433,7 +7388,7 @@ nsGlobalWindow::OpenInternal(const nsAString& aUrl, const nsAString& aName,
                   "Shouldn't have caller context when called noscript");
 
   *aReturn = nsnull;
-
+  
   nsCOMPtr<nsIWebBrowserChrome> chrome;
   GetWebBrowserChrome(getter_AddRefs(chrome));
   if (!chrome) {
@@ -9068,14 +9023,7 @@ nsGlobalModalWindow::GetDialogArguments(nsIArray **aArguments)
   FORWARD_TO_INNER_MODAL_CONTENT_WINDOW(GetDialogArguments, (aArguments),
                                         NS_ERROR_NOT_INITIALIZED);
 
-  PRBool subsumes = PR_FALSE;
-  nsIPrincipal *self = GetPrincipal();
-  if (self && NS_SUCCEEDED(self->Subsumes(mArgumentsOrigin, &subsumes)) &&
-      subsumes) {
-    NS_IF_ADDREF(*aArguments = mArguments);
-  } else {
-    *aArguments = nsnull;
-  }
+  *aArguments = mArguments;
 
   return NS_OK;
 }
@@ -9100,20 +9048,6 @@ nsGlobalModalWindow::SetReturnValue(nsIVariant *aRetVal)
   return NS_OK;
 }
 
-nsresult
-nsGlobalModalWindow::SetNewDocument(nsIDocument *aDocument,
-                                    nsISupports *aState,
-                                    PRBool aClearScopeHint)
-{
-  // If we're loading a new document into a modal dialog, clear the
-  // return value that was set, if any, by the current document.
-  if (aDocument) {
-    mReturnValue = nsnull;
-  }
-
-  return nsGlobalWindow::SetNewDocument(aDocument, aState, aClearScopeHint);
-}
-
 //*****************************************************************************
 // nsGlobalWindow: Creator Function (This should go away)
 //*****************************************************************************
diff --git a/dom/base/nsGlobalWindow.h b/dom/base/nsGlobalWindow.h
index 33ffdd2e411..94d789dacbc 100644
--- a/dom/base/nsGlobalWindow.h
+++ b/dom/base/nsGlobalWindow.h
@@ -261,6 +261,7 @@ public:
   
   virtual void OnFinalize(PRUint32 aLangID, void *aScriptGlobal);
   virtual void SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts);
+  virtual nsresult SetNewArguments(nsIArray *aArguments);
 
   // nsIScriptObjectPrincipal
   virtual nsIPrincipal* GetPrincipal();
@@ -337,8 +338,8 @@ public:
 
   virtual NS_HIDDEN_(void) SetDocShell(nsIDocShell* aDocShell);
   virtual NS_HIDDEN_(nsresult) SetNewDocument(nsIDocument *aDocument,
-                                              nsISupports *aState,
-                                              PRBool aClearScopeHint);
+                                  nsISupports *aState,
+                                  PRBool aClearScopeHint);
   virtual NS_HIDDEN_(void) SetOpenerWindow(nsIDOMWindowInternal *aOpener,
                                            PRBool aOriginalOpener);
   virtual NS_HIDDEN_(void) EnsureSizeUpToDate();
@@ -446,7 +447,6 @@ public:
   virtual void SetReadyForFocus();
   virtual void PageHidden();
   virtual nsresult DispatchAsyncHashchange();
-  virtual nsresult SetArguments(nsIArray *aArguments, nsIPrincipal *aOrigin);
 
   static PRBool DOMWindowDumpEnabled();
 
@@ -463,7 +463,6 @@ protected:
                           nsISupports *aState,
                           PRBool aClearScopeHint,
                           PRBool aIsInternalCall);
-  nsresult DefineArgumentsProperty(nsIArray *aArguments);
 
   // Get the parent, returns null if this is a toplevel window
   nsIDOMWindowInternal *GetParentInternal();
@@ -718,7 +717,6 @@ protected:
   nsCOMPtr<nsIControllers>      mControllers;
   nsCOMPtr<nsIArray>            mArguments;
   nsCOMPtr<nsIArray>            mArgumentsLast;
-  nsCOMPtr<nsIPrincipal>        mArgumentsOrigin;
   nsRefPtr<nsNavigator>         mNavigator;
   nsRefPtr<nsScreen>            mScreen;
   nsRefPtr<nsHistory>           mHistory;
@@ -840,10 +838,6 @@ public:
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsGlobalModalWindow, nsGlobalWindow)
 
-  virtual NS_HIDDEN_(nsresult) SetNewDocument(nsIDocument *aDocument,
-                                              nsISupports *aState,
-                                              PRBool aClearScopeHint);
-
 protected:
   nsCOMPtr<nsIVariant> mReturnValue;
 };
diff --git a/dom/base/nsIScriptGlobalObject.h b/dom/base/nsIScriptGlobalObject.h
index 88501bbba9d..84a5dd3567b 100644
--- a/dom/base/nsIScriptGlobalObject.h
+++ b/dom/base/nsIScriptGlobalObject.h
@@ -101,12 +101,13 @@ NS_HandleScriptError(nsIScriptGlobalObject *aScriptGlobal,
 
 
 #define NS_ISCRIPTGLOBALOBJECT_IID \
-{ 0xe9f3f2c1, 0x2d94, 0x4722, \
-  { 0xbb, 0xd4, 0x2b, 0xf6, 0xfd, 0xf4, 0x2f, 0x48 } }
+{ /* {6afecd40-0b9a-4cfd-8c42-0f645cd91829} */ \
+  0x6afecd40, 0x0b9a, 0x4cfd, \
+  { 0x8c, 0x42, 0x0f, 0x64, 0x5c, 0xd9, 0x18, 0x29 } }
 
 /**
-  * The global object which keeps a script context for each supported script
-  * language. This often used to store per-window global state.
++  * The global object which keeps a script context for each supported script
++  * language. This often used to store per-window global state.
  */
 
 class nsIScriptGlobalObject : public nsISupports
@@ -165,8 +166,15 @@ public:
    */
   virtual void SetScriptsEnabled(PRBool aEnabled, PRBool aFireTimeouts) = 0;
 
-  /**
-   * Handle a script error.  Generally called by a script context.
+  /** Set a new arguments object for this window. This will be set on
+   * the window right away (if there's an existing document) and it
+   * will also be installed on the window when the next document is
+   * loaded.  Each language impl is responsible for converting to
+   * an array of args as appropriate for that language.
+   */
+  virtual nsresult SetNewArguments(nsIArray *aArguments) = 0;
+
+  /** Handle a script error.  Generally called by a script context.
    */
   virtual nsresult HandleScriptError(nsScriptErrorEvent *aErrorEvent,
                                      nsEventStatus *aEventStatus) {
diff --git a/dom/base/nsPIDOMWindow.h b/dom/base/nsPIDOMWindow.h
index 369de3ad615..4be552e317b 100644
--- a/dom/base/nsPIDOMWindow.h
+++ b/dom/base/nsPIDOMWindow.h
@@ -75,11 +75,10 @@ class nsPresContext;
 struct nsTimeout;
 class nsScriptObjectHolder;
 class nsXBLPrototypeHandler;
-class nsIArray;
 
 #define NS_PIDOMWINDOW_IID \
-{ 0x70c9f57f, 0xf7b3, 0x4a37, \
-  { 0xbe, 0x36, 0xbb, 0xb2, 0xd7, 0xe9, 0x40, 0x13 } }
+{ 0x249423c9, 0x42a6, 0x8243, \
+  { 0x49, 0x45, 0x71, 0x7f, 0x8d, 0x28, 0x84, 0x43 } }
 
 class nsPIDOMWindow : public nsIDOMWindowInternal
 {
@@ -465,15 +464,6 @@ public:
    */
   virtual void SetHasOrientationEventListener() = 0;
 
-  /**
-   * Set a arguments for this window. This will be set on the window
-   * right away (if there's an existing document) and it will also be
-   * installed on the window when the next document is loaded. Each
-   * language impl is responsible for converting to an array of args
-   * as appropriate for that language.
-   */
-  virtual nsresult SetArguments(nsIArray *aArguments, nsIPrincipal *aOrigin) = 0;
-
 protected:
   // The nsPIDOMWindow constructor. The aOuterWindow argument should
   // be null if and only if the created window itself is an outer
diff --git a/dom/tests/mochitest/bugs/Makefile.in b/dom/tests/mochitest/bugs/Makefile.in
index 01c1153f7cf..498a3146ed9 100644
--- a/dom/tests/mochitest/bugs/Makefile.in
+++ b/dom/tests/mochitest/bugs/Makefile.in
@@ -100,8 +100,6 @@ _TEST_FILES	= \
 		test_bug484775.html \
 		test_bug427744.html \
 		test_bug495219.html \
-		test_bug504862.html \
-		file_bug504862.html \
 		$(NULL)
 
 libs:: 	$(_TEST_FILES)
diff --git a/dom/tests/mochitest/bugs/file_bug504862.html b/dom/tests/mochitest/bugs/file_bug504862.html
deleted file mode 100644
index c253c736e04..00000000000
--- a/dom/tests/mochitest/bugs/file_bug504862.html
+++ /dev/null
@@ -1,22 +0,0 @@
-<html>
-<body>
-<script>
-window.returnValue = 3;
-
-if (location.toString().match(/^http:\/\/localhost:8888/)) {
-  // Test that we got the right arguments.
-  opener.is(window.dialogArguments, "my args",
-            "dialog did not get the right arguments.");
-
-  // Load a different url, and test that it doesn't see the arguments.
-  window.location="data:text/html,<html><body onload=\"opener.is(window.dialogArguments, null, 'subsequent dialog document did not get the right arguments.'); close();\">';";
-} else {
-  // Post a message containing our arguments to the opener to test
-  // that this cross origing dialog does *not* see the passed in
-  // arguments.
-  opener.postMessage("args: " + window.dialogArguments,
-                     "http://localhost:8888");
-
-  close();
-}
-</script>
diff --git a/dom/tests/mochitest/bugs/test_bug504862.html b/dom/tests/mochitest/bugs/test_bug504862.html
deleted file mode 100644
index cecebe1fc68..00000000000
--- a/dom/tests/mochitest/bugs/test_bug504862.html
+++ /dev/null
@@ -1,37 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=504862
--->
-<head>
-  <title>Test for Bug 504862</title>
-  <script type="text/javascript" src="/MochiKit/packed.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=504862">Mozilla Bug 504862</a>
-<script class="testbody" type="text/javascript">
-
-/** Test for Bug 504862 **/
-
-function onMsgRcv(event)
-{
-  is(event.data, "args: undefined", "Unexpected cross origin dialog arguments.");
-}
-
-window.addEventListener("message", onMsgRcv, false);
-
-var subsequentDlg = "data:text/html,<html><body onload='opener.is(window.dialogArguments, \'my args\', \'subsequent dialog document did not get the right arguments.\'); close();'>";
-
-var result = window.showModalDialog("file_bug504862.html", "my args");
-is(result, null, "window sees previous dialog documents return value.");
-
-result = window.showModalDialog("http://test1.example.com/tests/dom/tests/mochitest/bugs/file_bug504862.html", "my args");
-
-is(result, null, "Able to see return value from cross origin dialog.");
-
-</script>
-</pre>
-</body>
-</html>
diff --git a/embedding/components/windowwatcher/src/nsWindowWatcher.cpp b/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
index cec251016f7..4631be3956b 100644
--- a/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
+++ b/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
@@ -60,7 +60,6 @@
 #include "nsIDOMWindow.h"
 #include "nsIDOMChromeWindow.h"
 #include "nsIDOMWindowInternal.h"
-#include "nsIDOMModalContentWindow.h"
 #include "nsIScriptObjectPrincipal.h"
 #include "nsIScreen.h"
 #include "nsIScreenManager.h"
@@ -574,21 +573,11 @@ nsWindowWatcher::OpenWindowJSInternal(nsIDOMWindow *aParent,
   SizeSpec sizeSpec;
   CalcSizeSpec(features.get(), sizeSpec);
 
+  PRBool isCallerChrome = PR_FALSE;
   nsCOMPtr<nsIScriptSecurityManager>
     sm(do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID));
-
-  // Remember who's calling us. This code used to assume a null
-  // subject principal if it failed to get the principal, but that's
-  // just not safe, so bail on errors here.
-  nsCOMPtr<nsIPrincipal> callerPrincipal;
-  rv = sm->GetSubjectPrincipal(getter_AddRefs(callerPrincipal));
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  PRBool isCallerChrome = PR_TRUE;
-  if (callerPrincipal) {
-    rv = sm->IsSystemPrincipal(callerPrincipal, &isCallerChrome);
-    NS_ENSURE_SUCCESS(rv, rv);
-  }
+  if (sm)
+    sm->SubjectPrincipalIsSystem(&isCallerChrome);
 
   JSContext *cx = GetJSContextFromWindow(aParent);
 
@@ -767,10 +756,9 @@ nsWindowWatcher::OpenWindowJSInternal(nsIDOMWindow *aParent,
 
   if ((aDialog || windowIsModalContentDialog) && argv) {
     // Set the args on the new window.
-    nsCOMPtr<nsPIDOMWindow> piwin(do_QueryInterface(*_retval));
-    NS_ENSURE_TRUE(piwin, NS_ERROR_UNEXPECTED);
-
-    rv = piwin->SetArguments(argv, callerPrincipal);
+    nsCOMPtr<nsIScriptGlobalObject> scriptGlobal(do_QueryInterface(*_retval));
+    NS_ENSURE_TRUE(scriptGlobal, NS_ERROR_UNEXPECTED);
+    rv = scriptGlobal->SetNewArguments(argv);
     NS_ENSURE_SUCCESS(rv, rv);
   }