Choose the correct icon size for Windows taskbar

atom/browser/api/atom_api_window.cc

@@ -633,7 +633,8 @@ void Window::ShowDefinitionForSelection() {
 void Window::SetIcon(mate::Handle<NativeImage> icon) {
 #if defined(OS_WIN)
   static_cast<NativeWindowViews*>(window_.get())->SetIcon(
-      icon->GetHICON(GetSystemMetrics(SM_CXSMICON)), icon->GetHICON(256));
+      icon->GetHICON(GetSystemMetrics(SM_CXSMICON)),
+      icon->GetHICON(GetSystemMetrics(SM_CXICON)));
 #elif defined(USE_X11)
   static_cast<NativeWindowViews*>(window_.get())->SetIcon(
       icon->image().AsImageSkia());

docs/api/native-image.md

@@ -30,6 +30,7 @@ effects it is recommended to include at least followings sizes in the icon:
 
 * 16x16
 * 32x32
+* 64x64
 * 256x256
 
 ## High Resolution Image