wifi: Disable RSSI polling when the screen is off.

Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/services/java/com/android/server/WifiService.java b/services/java/com/android/server/WifiService.java
index 01394ad..b4754b6 100644
--- a/services/java/com/android/server/WifiService.java
+++ b/services/java/com/android/server/WifiService.java
@@ -192,6 +192,7 @@
     WifiService(Context context, WifiStateTracker tracker) {
         mContext = context;
         mWifiStateTracker = tracker;
+        mWifiStateTracker.enableRssiPolling(true);
         mBatteryStats = BatteryStatsService.getService();
         
         /*
@@ -1560,9 +1561,11 @@
                 mAlarmManager.cancel(mIdleIntent);
                 mDeviceIdle = false;
                 mScreenOff = false;
+                mWifiStateTracker.enableRssiPolling(true);
             } else if (action.equals(Intent.ACTION_SCREEN_OFF)) {
                 Log.d(TAG, "ACTION_SCREEN_OFF");
                 mScreenOff = true;
+                mWifiStateTracker.enableRssiPolling(false);
                 /*
                  * Set a timer to put Wi-Fi to sleep, but only if the screen is off
                  * AND the "stay on while plugged in" setting doesn't match the