Stop SkyShell from crashing on startup

R=chinmaygarde@google.com

Review URL: https://codereview.chromium.org/1178773002.

shell/android/platform_view_android.h

@@ -25,8 +25,6 @@ class PlatformViewAndroid : public PlatformView {
  private:
   void ReleaseWindow();
 
-  ANativeWindow* window_;
-
   DISALLOW_COPY_AND_ASSIGN(PlatformViewAndroid);
 };