Bug 355430 - Add the thrown error object to the dom error event. r=bz

dom/base/nsJSEnvironment.cpp

@@ -431,6 +431,7 @@ public:
                    nsIPrincipal* aScriptOriginPrincipal,
                    nsIPrincipal* aGlobalPrincipal,
                    nsPIDOMWindow* aWindow,
+                   JS::Handle<JS::Value> aError,
                    bool aDispatchEvent)
     // Pass an empty category, then compute ours
     : AsyncErrorReporter(aRuntime, aErrorReport, aFallbackMessage,
@@ -439,6 +440,7 @@ public:
     , mScriptGlobal(aScriptGlobal)
     , mOriginPrincipal(aScriptOriginPrincipal)
     , mDispatchEvent(aDispatchEvent)
+    , mError(aRuntime, aError)
   {
   }
 
@@ -458,7 +460,8 @@ public:
         nsRefPtr<nsPresContext> presContext;
         docShell->GetPresContext(getter_AddRefs(presContext));
 
-        ErrorEventInit init;
+        ThreadsafeAutoJSContext cx;
+        RootedDictionary<ErrorEventInit> init(cx);
         init.mCancelable = true;
         init.mFilename = mFileName;
         init.mBubbles = true;
@@ -480,6 +483,7 @@ public:
         if (sameOrigin) {
           init.mMessage = mErrorMsg;
           init.mLineno = mLineNumber;
+          init.mError = mError;
         } else {
           NS_WARNING("Not same origin error!");
           init.mMessage = xoriginMsg;
@@ -507,6 +511,7 @@ private:
   nsCOMPtr<nsIScriptGlobalObject> mScriptGlobal;
   nsCOMPtr<nsIPrincipal>          mOriginPrincipal;
   bool                            mDispatchEvent;
+  JS::PersistentRootedValue       mError;
 
   static bool sHandlingScriptError;
 };
@@ -551,6 +556,9 @@ NS_ScriptErrorReporter(JSContext *cx,
   // XXX this means we are not going to get error reports on non DOM contexts
   nsIScriptContext *context = nsJSUtils::GetDynamicScriptContext(cx);
 
+  JS::Rooted<JS::Value> exception(cx);
+  ::JS_GetPendingException(cx, &exception);
+
   // Note: we must do this before running any more code on cx (if cx is the
   // dynamic script context).
   ::JS_ClearPendingException(cx);
@@ -573,6 +581,7 @@ NS_ScriptErrorReporter(JSContext *cx,
                              nsJSPrincipals::get(report->originPrincipals),
                              scriptPrincipal->GetPrincipal(),
                              win,
+                             exception,
                              /* We do not try to report Out Of Memory via a dom
                               * event because the dom event handler would
                               * encounter an OOM exception trying to process the

dom/events/nsJSEventListener.cpp

@@ -165,6 +165,7 @@ nsJSEventListener::HandleEvent(nsIDOMEvent* aEvent)
     Optional<nsAString> fileName;
     Optional<uint32_t> lineNumber;
     Optional<uint32_t> columnNumber;
+    Optional<JS::Handle<JS::Value>> error;
 
     NS_ENSURE_TRUE(aEvent, NS_ERROR_UNEXPECTED);
     ErrorEvent* scriptEvent = aEvent->InternalDOMEvent()->AsErrorEvent();
@@ -177,6 +178,10 @@ nsJSEventListener::HandleEvent(nsIDOMEvent* aEvent)
 
       lineNumber.Construct();
       lineNumber.Value() = scriptEvent->Lineno();
+
+      ThreadsafeAutoJSContext cx;
+      error.Construct(cx);
+      error.Value() = scriptEvent->Error(cx);
     } else {
       msgOrEvent.SetAsEvent() = aEvent->InternalDOMEvent();
     }
@@ -185,7 +190,7 @@ nsJSEventListener::HandleEvent(nsIDOMEvent* aEvent)
       mHandler.OnErrorEventHandler();
     ErrorResult rv;
     bool handled = handler->Call(mTarget, msgOrEvent, fileName, lineNumber,
-                                 columnNumber, rv);
+                                 columnNumber, error, rv);
     if (rv.Failed()) {
       return rv.ErrorCode();
     }

dom/webidl/ErrorEvent.webidl

@@ -10,6 +10,7 @@ interface ErrorEvent : Event
   readonly attribute DOMString filename;
   readonly attribute unsigned long lineno;
   readonly attribute unsigned long column;
+  readonly attribute any error;
 };
 
 dictionary ErrorEventInit : EventInit
@@ -18,4 +19,5 @@ dictionary ErrorEventInit : EventInit
   DOMString filename = "";
   unsigned long lineno = 0;
   unsigned long column = 0;
+  any error = null;
 };

dom/webidl/EventHandler.webidl

@@ -21,7 +21,7 @@ callback OnBeforeUnloadEventHandlerNonNull = DOMString? (Event event);
 typedef OnBeforeUnloadEventHandlerNonNull? OnBeforeUnloadEventHandler;
 
 [TreatNonObjectAsNull]
-callback OnErrorEventHandlerNonNull = boolean ((Event or DOMString) event, optional DOMString source, optional unsigned long lineno, optional unsigned long column);
+callback OnErrorEventHandlerNonNull = boolean ((Event or DOMString) event, optional DOMString source, optional unsigned long lineno, optional unsigned long column, optional any error);
 typedef OnErrorEventHandlerNonNull? OnErrorEventHandler;
 
 [NoInterfaceObject]

dom/workers/WorkerPrivate.cpp

@@ -1185,7 +1185,7 @@ public:
     // they show up in the error console.
     if (!JSREPORT_IS_WARNING(aFlags)) {
       // First fire an ErrorEvent at the worker.
-      ErrorEventInit init;
+      RootedDictionary<ErrorEventInit> init(aCx);
       init.mMessage = aMessage;
       init.mFilename = aFilename;
       init.mLineno = aLineNumber;
@@ -3135,7 +3135,7 @@ WorkerPrivateParent<Derived>::BroadcastErrorToSharedWorkers(
       continue;
     }
 
-    ErrorEventInit errorInit;
+    RootedDictionary<ErrorEventInit> errorInit(aCx);
     errorInit.mBubbles = false;
     errorInit.mCancelable = true;
     errorInit.mMessage = aMessage;
@@ -3201,7 +3201,7 @@ WorkerPrivateParent<Derived>::BroadcastErrorToSharedWorkers(
     MOZ_ASSERT(sgo);
 
     MOZ_ASSERT(NS_IsMainThread());
-    ErrorEventInit init;
+    RootedDictionary<ErrorEventInit> init(aCx);
     init.mLineno = aLineNumber;
     init.mFilename = aFilename;
     init.mMessage = aMessage;