Accquire a wakelock while encrypting.

Bug: 3375491
Change-Id: Ief7dbb450800104f4977ab31f93a1e1a994b25ad

src/com/android/settings/CryptKeeper.java

@@ -30,6 +30,7 @@ import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
 import android.os.Message;
+import android.os.PowerManager;
 import android.os.ServiceManager;
 import android.os.SystemProperties;
 import android.os.storage.IMountService;
@@ -137,6 +138,15 @@ public class CryptKeeper extends Activity implements TextView.OnEditorActionList
     }
 
     private void encryptionProgressInit() {
+        // Accquire a partial wakelock to prevent the device from sleeping. Note
+        // we never release this wakelock as we will be restarted after the device
+        // is encrypted.
+
+        PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
+        PowerManager.WakeLock wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
+
+        wakeLock.acquire();
+
         mHandler.sendEmptyMessage(UPDATE_PROGRESS);
     }