Disable bubbles for low ram devices

Fixes: 167677013
Test: set low ram true => bubble settings hidden
Test: make -j80 RunSettingsRoboTests ROBOTEST_FILTER="Bubble"

Change-Id: I1c40a05404ea7c78cc82102b33e4bc3cb3528075

src/com/android/settings/notification/BubbleSummaryNotificationPreferenceController.java

@@ -18,6 +18,7 @@ package com.android.settings.notification;
 
 import static android.provider.Settings.Global.NOTIFICATION_BUBBLES;
 
+import android.app.ActivityManager;
 import android.content.Context;
 import android.provider.Settings;
 
@@ -48,7 +49,8 @@ public class BubbleSummaryNotificationPreferenceController extends BasePreferenc
 
     @Override
     public int getAvailabilityStatus() {
-        return AVAILABLE;
+        ActivityManager am = mContext.getSystemService(ActivityManager.class);
+        return am.isLowRamDevice() ? UNSUPPORTED_ON_DEVICE : AVAILABLE;
     }
 
     private boolean areBubblesEnabled() {