* 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
v8::Isolate* isolate, v8::Local<v8::FunctionTemplate> prototype) {
  prototype->SetClassName(mate::StringToV8(isolate, "WebFrame"));
  mate::ObjectTemplateBuilder(isolate, prototype->PrototypeTemplate())
      .SetMethod("setName", &WebFrame::SetName)
      .SetMethod("setZoomLevel", &WebFrame::SetZoomLevel)
      .SetMethod("getZoomLevel", &WebFrame::GetZoomLevel)
      .SetMethod("setZoomFactor", &WebFrame::SetZoomFactor)
      .SetMethod("getZoomFactor", &WebFrame::GetZoomFactor)
      .SetMethod("setVisualZoomLevelLimits",
                 &WebFrame::SetVisualZoomLevelLimits)
      .SetMethod("setLayoutZoomLevelLimits",
                 &WebFrame::SetLayoutZoomLevelLimits)
      .SetMethod("registerEmbedderCustomElement",
                 &WebFrame::RegisterEmbedderCustomElement)
      .SetMethod("registerElementResizeCallback",
                 &WebFrame::RegisterElementResizeCallback)
      .SetMethod("attachGuest", &WebFrame::AttachGuest)
      .SetMethod("detachGuest", &WebFrame::DetachGuest)
      .SetMethod("setSpellCheckProvider", &WebFrame::SetSpellCheckProvider)
      .SetMethod("registerURLSchemeAsSecure",
                 &WebFrame::RegisterURLSchemeAsSecure)
      .SetMethod("registerURLSchemeAsBypassingCSP",
                 &WebFrame::RegisterURLSchemeAsBypassingCSP)
      .SetMethod("registerURLSchemeAsPrivileged",
                 &WebFrame::RegisterURLSchemeAsPrivileged)
      .SetMethod("insertText", &WebFrame::InsertText)
      .SetMethod("insertCSS", &WebFrame::InsertCSS)
      .SetMethod("executeJavaScript", &WebFrame::ExecuteJavaScript)
      .SetMethod("executeJavaScriptInIsolatedWorld",
                 &WebFrame::ExecuteJavaScriptInIsolatedWorld)