[Win] Fix black screen when min/maximizing hidden app window.

chrome/browser/ui/views/apps/app_window_desktop_native_widget_aura_win.h

Index: chrome/browser/ui/views/apps/app_window_desktop_native_widget_aura_win.h
diff --git a/chrome/browser/ui/views/apps/app_window_desktop_native_widget_aura_win.h b/chrome/browser/ui/views/apps/app_window_desktop_native_widget_aura_win.h
index 43bc8a75f7ef8707192a40fa3bde969f5cfa6aa5..75f34646fcf325ed642d873a3da91c0a0c543e95 100644
--- a/chrome/browser/ui/views/apps/app_window_desktop_native_widget_aura_win.h
+++ b/chrome/browser/ui/views/apps/app_window_desktop_native_widget_aura_win.h
@@ -12,6 +12,10 @@ class BrowserFrame;
 class BrowserView;
 class ChromeNativeAppWindowViewsWin;
 
+namespace views {
+class DesktopWindowTreeHost;
+}
+
 namespace wm {
 class VisibilityController;
 }
@@ -30,11 +34,16 @@ class AppWindowDesktopNativeWidgetAuraWin
   // Overridden from views::DesktopNativeWidgetAura:
   virtual void InitNativeWidget(
       const views::Widget::InitParams& params) override;
+  void Maximize() override;
+  void Minimize() override;
 
  private:
   // Ownership managed by the views system.
   ChromeNativeAppWindowViewsWin* app_window_;
 
+  // Owned by superclass DesktopNativeWidgetAura.
+  views::DesktopWindowTreeHost* tree_host_;
+
   DISALLOW_COPY_AND_ASSIGN(AppWindowDesktopNativeWidgetAuraWin);
 };