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* Electron version: 1.7.2
* Operating system: macOS Sierra

### Expected behavior

Webview appear

### Actual behavior

It don't

### How to reproduce

1. Create a browser window with contextIsolation on true and webviewTag on true
2. Inside of it, add a webview
3. Run it, webview should not appear

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atom/renderer/atom_renderer_client.h
void RenderViewCreated(content::RenderView*) override;
  void RunScriptsAtDocumentStart(content::RenderFrame* render_frame) override;
  void RunScriptsAtDocumentEnd(content::RenderFrame* render_frame) override;
  bool ShouldFork(blink::WebLocalFrame* frame,
                  const GURL& url,
                  const std::string& http_method,
                  bool is_initial_navigation,
                  bool is_server_redirect) override;
  void DidInitializeWorkerContextOnWorkerThread(
      v8::Local<v8::Context> context) override;
  void WillDestroyWorkerContextOnWorkerThread(
      v8::Local<v8::Context> context) override;
  node::Environment* GetEnvironment(content::RenderFrame* frame) const;
  
  bool node_integration_initialized_ = false;
  std::unique_ptr<NodeBindings> node_bindings_;
  std::unique_ptr<AtomBindings> atom_bindings_;
  
  
  
  std::set<node::Environment*> environments_;
  
  
  
  std::set<content::RenderFrame*> injected_frames_;
  DISALLOW_COPY_AND_ASSIGN(AtomRendererClient);
};
}  
#endif