Fix crash on "Connection preferences"

This CL adds a null check condition to avoid crash for
some device not support PrintManager.

Bug: 159848003
Test: make -j42 SettingsGoogle
Change-Id: Ic6c4c17bb563458f4f5a61dc0d93ae22b05f8763

src/com/android/settings/print/PrintSettingPreferenceController.java

@@ -60,6 +60,7 @@ public class PrintSettingPreferenceController extends BasePreferenceController i
     @Override
     public int getAvailabilityStatus() {
         return mPackageManager.hasSystemFeature(PackageManager.FEATURE_PRINTING)
+                && mPrintManager != null
                 ? AVAILABLE : UNSUPPORTED_ON_DEVICE;
     }
 
@@ -71,12 +72,16 @@ public class PrintSettingPreferenceController extends BasePreferenceController i
 
     @Override
     public void onStart() {
-        mPrintManager.addPrintJobStateChangeListener(this);
+        if (mPrintManager != null) {
+            mPrintManager.addPrintJobStateChangeListener(this);
+        }
     }
 
     @Override
     public void onStop() {
-        mPrintManager.removePrintJobStateChangeListener(this);
+        if (mPrintManager != null) {
+            mPrintManager.removePrintJobStateChangeListener(this);
+        }
     }
 
     @Override