Bug 1000175. Make sure error events on window only fire if the active document has not changed from when the exception was thrown. r=smaug

dom/base/nsJSEnvironment.cpp

@@ -386,10 +386,8 @@ AsyncErrorReporter::AsyncErrorReporter(JSRuntime* aRuntime,
                                NS_LITERAL_CSTRING("content javascript");
 
   mInnerWindowID = 0;
-  if (aWindow && aWindow->IsOuterWindow()) {
-    aWindow = aWindow->GetCurrentInnerWindow();
-  }
   if (aWindow) {
+    MOZ_ASSERT(aWindow->IsInnerWindow());
     mInnerWindowID = aWindow->WindowID();
   }
 }
@@ -427,8 +425,7 @@ AsyncErrorReporter::ReportError()
 class ScriptErrorEvent : public AsyncErrorReporter
 {
 public:
-  ScriptErrorEvent(nsIScriptGlobalObject* aScriptGlobal,
-                   JSRuntime* aRuntime,
+  ScriptErrorEvent(JSRuntime* aRuntime,
                    JSErrorReport* aErrorReport,
                    const char* aFallbackMessage,
                    nsIPrincipal* aScriptOriginPrincipal,
@@ -440,20 +437,21 @@ public:
     : AsyncErrorReporter(aRuntime, aErrorReport, aFallbackMessage,
                          nsContentUtils::IsSystemPrincipal(aGlobalPrincipal),
                          aWindow)
-    , mScriptGlobal(aScriptGlobal)
     , mOriginPrincipal(aScriptOriginPrincipal)
     , mDispatchEvent(aDispatchEvent)
     , mError(aRuntime, aError)
+    , mWindow(aWindow)
   {
+    MOZ_ASSERT_IF(mWindow, mWindow->IsInnerWindow());
   }
 
   NS_IMETHOD Run()
   {
     nsEventStatus status = nsEventStatus_eIgnore;
-    // First, notify the DOM that we have a script error.
-    if (mDispatchEvent) {
-      nsCOMPtr<nsPIDOMWindow> win(do_QueryInterface(mScriptGlobal));
-      nsIDocShell* docShell = win ? win->GetDocShell() : nullptr;
+    // First, notify the DOM that we have a script error, but only if
+    // our window is still the current inner, if we're associated with a window.
+    if (mDispatchEvent && (!mWindow || mWindow->IsCurrentInnerWindow())) {
+      nsIDocShell* docShell = mWindow ? mWindow->GetDocShell() : nullptr;
       if (docShell &&
           !JSREPORT_IS_WARNING(mFlags) &&
           !sHandlingScriptError) {
@@ -469,7 +467,7 @@ public:
         init.mFilename = mFileName;
         init.mBubbles = true;
 
-        nsCOMPtr<nsIScriptObjectPrincipal> sop(do_QueryInterface(win));
+        nsCOMPtr<nsIScriptObjectPrincipal> sop(do_QueryInterface(mWindow));
         NS_ENSURE_STATE(sop);
         nsIPrincipal* p = sop->GetPrincipal();
         NS_ENSURE_STATE(p);
@@ -495,11 +493,11 @@ public:
         }
 
         nsRefPtr<ErrorEvent> event =
-          ErrorEvent::Constructor(static_cast<nsGlobalWindow*>(win.get()),
+          ErrorEvent::Constructor(static_cast<nsGlobalWindow*>(mWindow.get()),
                                   NS_LITERAL_STRING("error"), init);
         event->SetTrusted(true);
 
-        EventDispatcher::DispatchDOMEvent(win, nullptr, event, presContext,
+        EventDispatcher::DispatchDOMEvent(mWindow, nullptr, event, presContext,
                                           &status);
       }
     }
@@ -512,10 +510,10 @@ public:
   }
 
 private:
-  nsCOMPtr<nsIScriptGlobalObject> mScriptGlobal;
   nsCOMPtr<nsIPrincipal>          mOriginPrincipal;
   bool                            mDispatchEvent;
   JS::PersistentRootedValue       mError;
+  nsCOMPtr<nsPIDOMWindow>         mWindow;
 
   static bool sHandlingScriptError;
 };
@@ -573,13 +571,15 @@ NS_ScriptErrorReporter(JSContext *cx,
     if (globalObject) {
 
       nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(globalObject);
+      if (win) {
+        win = win->GetCurrentInnerWindow();
+      }
       nsCOMPtr<nsIScriptObjectPrincipal> scriptPrincipal =
         do_QueryInterface(globalObject);
       NS_ASSERTION(scriptPrincipal, "Global objects must implement "
                    "nsIScriptObjectPrincipal");
       nsContentUtils::AddScriptRunner(
-        new ScriptErrorEvent(globalObject,
-                             JS_GetRuntime(cx),
+        new ScriptErrorEvent(JS_GetRuntime(cx),
                              report,
                              message,
                              nsJSPrincipals::get(report->originPrincipals),