- Electron version: 1.4.0
- Operating system: OS X 10.10.5

I've been using the following code to send Tab key events to a webview in my project:

``` js
const webContents = webView.getWebContents();
const keyEvent = {
  type: 'keyDown',
  keyCode: 'Tab'
};

webContents.sendInputEvent(keyEvent);
```

I have had no issues with this until the recent update to 1.4.0.

The last version the above code works in OS X is **1.3.7**. I've tried this with the latest versions of Electron (1.4.1 & 1.4.2) with the same results.

Am I doing something wrong here? Is this a known issue?

atom/common/native_mate_converters/blink_converter.cc
v8::Isolate* isolate, v8::Local<v8::Value> val,
    content::NativeWebKeyboardEvent* out) {
  mate::Dictionary dict;
  if (!ConvertFromV8(isolate, val, &dict))
    return false;
  if (!ConvertFromV8(isolate, val, static_cast<blink::WebKeyboardEvent*>(out)))
    return false;
  dict.Get("skipInBrowser", &out->skip_in_browser);
  return true;
}
bool Converter<blink::WebMouseEvent>::FromV8(
    v8::Isolate* isolate, v8::Local<v8::Value> val, blink::WebMouseEvent* out) {
  mate::Dictionary dict;
  if (!ConvertFromV8(isolate, val, &dict))
    return false;
  if (!ConvertFromV8(isolate, val, static_cast<blink::WebInputEvent*>(out)))
    return false;
  if (!dict.Get("x", &out->x) || !dict.Get("y", &out->y))
    return false;
  if (!dict.Get("button", &out->button))
    out->button = blink::WebMouseEvent::Button::ButtonLeft;
  dict.Get("globalX", &out->globalX);
  dict.Get("globalY", &out->globalY);
  dict.Get("movementX", &out->movementX);
  dict.Get("movementY", &out->movementY);
  dict.Get("clickCount", &out->clickCount);
  return true;
}
bool Converter<blink::WebMouseWheelEvent>::FromV8(