* 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
#include "atom/renderer/api/atom_api_web_frame.h"
#include "atom/common/api/api_messages.h"
#include "atom/common/api/event_emitter_caller.h"
#include "atom/common/native_mate_converters/blink_converter.h"
#include "atom/common/native_mate_converters/callback.h"
#include "atom/common/native_mate_converters/gfx_converter.h"
#include "atom/common/native_mate_converters/string16_converter.h"
#include "atom/renderer/api/atom_api_spell_check_client.h"
#include "base/memory/memory_pressure_listener.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_frame_visitor.h"
#include "content/public/renderer/render_view.h"
#include "native_mate/dictionary.h"
#include "native_mate/object_template_builder.h"
#include "third_party/WebKit/public/platform/WebCache.h"
#include "third_party/WebKit/public/web/WebDocument.h"
#include "third_party/WebKit/public/web/WebElement.h"
#include "third_party/WebKit/public/web/WebFrameWidget.h"
#include "third_party/WebKit/public/web/WebImeTextSpan.h"
#include "third_party/WebKit/public/web/WebInputMethodController.h"
#include "third_party/WebKit/public/web/WebLocalFrame.h"
#include "third_party/WebKit/public/web/WebScriptExecutionCallback.h"
#include "third_party/WebKit/public/web/WebScriptSource.h"