* Electron version: 1.7.9
* Operating system: macOS 10.13.1

### Expected behavior

If pinch-zoom is disabled via `webFrame.setVisualZoomLevelLimits(1, 1);` it should stay disabled.

### Actual behavior

Pinch zoom is possible. 

### How to reproduce

* connect an external monitor and open any electron app there, keep the macbook pro lid closed
* disconnect the external monitor
* open the lid

=> you can now pinch zoom 
atom/renderer/api/atom_api_web_frame.cc
public:
  using CompletionCallback =
      base::Callback<void(
          const v8::Local<v8::Value>& result)>;
  explicit ScriptExecutionCallback(const CompletionCallback& callback)
      : callback_(callback) {}
  ~ScriptExecutionCallback() override {}
  void Completed(
      const blink::WebVector<v8::Local<v8::Value>>& result) override {
    if (!callback_.is_null() && !result.IsEmpty() && !result[0].IsEmpty())
      
      callback_.Run(result[0]);
    delete this;
  }
 private:
  CompletionCallback callback_;
  DISALLOW_COPY_AND_ASSIGN(ScriptExecutionCallback);
};
class FrameSpellChecker : public content::RenderFrameVisitor {