Add 'blur' window event.

browser/api/atom_api_window.cc

@@ -67,6 +67,10 @@ void Window::OnWindowClosed() {
   delete this;
 }
 
+void Window::OnWindowBlur() {
+  Emit("blur");
+}
+
 // static
 v8::Handle<v8::Value> Window::New(const v8::Arguments &args) {
   v8::HandleScope scope;

browser/api/atom_api_window.h

@@ -37,6 +37,7 @@ class Window : public EventEmitter,
                                   const std::string& title) OVERRIDE;
   virtual void WillCloseWindow(bool* prevent_default) OVERRIDE;
   virtual void OnWindowClosed() OVERRIDE;
+  virtual void OnWindowBlur() OVERRIDE;
 
  private:
   static v8::Handle<v8::Value> New(const v8::Arguments &args);