Don't show keyguard on top of CryptKeeper

The fix in Change Ifbe4cdf40e3b76d2069ecace940f85fa58f31187 causes
keyguard to be more aggressive about showing itself.

CryptKeeper itself should explicitly dismiss keyguard.

Fixes bug 11680832

Change-Id: I87287762b73bdffc6f1800379f02f70f4bd873a8
diff --git a/src/com/android/settings/CryptKeeper.java b/src/com/android/settings/CryptKeeper.java
index 7057f1a..23ec70e 100644
--- a/src/com/android/settings/CryptKeeper.java
+++ b/src/com/android/settings/CryptKeeper.java
@@ -43,6 +43,7 @@
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.WindowManager;
 import android.view.View.OnClickListener;
 import android.view.View.OnKeyListener;
 import android.view.View.OnTouchListener;
@@ -557,6 +558,9 @@
         // Notify the user in 120 seconds that we are waiting for him to enter the password.
         mHandler.removeMessages(MESSAGE_NOTIFY);
         mHandler.sendEmptyMessageDelayed(MESSAGE_NOTIFY, 120 * 1000);
+
+        // Dismiss keyguard while this screen is showing.
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
     }
 
     /**