text: #import <GGLCore/GGLCore.h>
  
  /**
   * This category extends |GGLContext| with the Google Sign In service. To
   * integrate, import GGLContext+SignIn.h.
   *
   * [GIDSignIn sharedInstance] should be ready to use after calling
   * -[[GGLContext sharedInstance] configureWithError:].
   *
   * @see GGLContext
   */
  @interface GGLContext (SignIn)
  
  @end
  