Wires up new launcher images. To get the official images for the

ui/aura_shell/shell_delegate.h

Index: ui/aura_shell/shell_delegate.h
diff --git a/ui/aura_shell/shell_delegate.h b/ui/aura_shell/shell_delegate.h
index 3771b1aa12ea4358e986793e9b8d7491a59d5b3e..1239bc83283cf5593c3c508fb43fab91595ded99 100644
--- a/ui/aura_shell/shell_delegate.h
+++ b/ui/aura_shell/shell_delegate.h
@@ -50,8 +50,11 @@ class AURA_SHELL_EXPORT ShellDelegate {
   // an entry for |item->window| it should configure |item| appropriately and
   // return true.
   virtual bool ConfigureLauncherItem(LauncherItem* item) = 0;
-};
 
+  // Returns the resource id of the image to show on the button that creates a
+  // new browser window.
+  virtual int GetResourceIDForNewBrowserWindow() = 0;
+};
 }  // namespace aura_shell
 
 #endif  // UI_AURA_SHELL_SHELL_DELEGATE_H_