Fix unhandled promise console message to show stack trace of a DOMException.

Source/bindings/core/v8/V8Initializer.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 230 matching lines @@
     if (global.IsEmpty())
         return;
     if (!toFrameIfNotDetached(context))
         return;
 
     RefPtrWillBeRawPtr<ScriptCallStack> callStack = nullptr;
     v8::Handle<v8::StackTrace> stackTrace = message.GetStackTrace();
     if (!stackTrace.IsEmpty() && stackTrace->GetFrameCount() > 0)
         callStack = createScriptCallStack(stackTrace, ScriptCallStack::maxCallStackSizeToCapture, isolate);
 
+    if (!callStack && V8DOMWrapper::isDOMWrapper(message.GetValue())) {
+        // Try to get the stack from a wrapped exception object (e.g. DOMException).
+        v8::Handle<v8::Object> obj = v8::Handle<v8::Object>::Cast(message.GetValue());
+        v8::Handle<v8::Value> error = V8HiddenValue::getHiddenValue(isolate, obj, V8HiddenValue::error(isolate));
+        if (!error.IsEmpty()) {
+            stackTrace = v8::Exception::GetStackTrace(error);
+            if (!stackTrace.IsEmpty() && stackTrace->GetFrameCount() > 0)
+                callStack = createScriptCallStack(stackTrace, ScriptCallStack::maxCallStackSizeToCapture, isolate);
+        }
+    }
+
     ScriptState* scriptState = ScriptState::from(context);
     promiseRejectMessageQueue().append(PromiseRejectMessage(ScriptValue(scriptState, promise), callStack));
 }
 
 static void failedAccessCheckCallbackInMainThread(v8::Local<v8::Object> host, v8::AccessType type, v8::Local<v8::Value> data)
 {
     v8::Isolate* isolate = v8::Isolate::GetCurrent();
     LocalFrame* target = findFrame(host, data, isolate);
     if (!target)
         return;
@@ skipping 103 matching lines @@
     initializeV8Common(isolate);
 
     v8::V8::AddMessageListener(messageHandlerInWorker);
     v8::V8::SetFatalErrorHandler(reportFatalErrorInWorker);
 
     uint32_t here;
     isolate->SetStackLimit(reinterpret_cast<uintptr_t>(&here - kWorkerMaxStackSize / sizeof(uint32_t*)));
 }
 
 } // namespace blink