Report all conditions met when no conditions given.

Test: atest ConditionMonitorTest#addCallback_noConditions_reportAllConditionsMet
Fix: 209015016
Change-Id: Ieb81d659fbaf6123d6a8a8d6f5b3d8b300299c40

packages/SystemUI/src/com/android/systemui/util/condition/Monitor.java

@@ -81,6 +81,12 @@ public class Monitor implements CallbackController<Monitor.Callback> {
     public Monitor(Set<Condition> conditions) {
         mConditions = conditions;
 
+        // If there is no condition, give green pass.
+        if (mConditions.isEmpty()) {
+            mAllConditionsMet = true;
+            return;
+        }
+
         // Initializes the conditions map and registers a callback for each condition.
         mConditions.forEach((condition -> mConditionsMap.put(condition, false)));
     }

packages/SystemUI/tests/src/com/android/systemui/util/condition/ConditionMonitorTest.java

@@ -96,6 +96,16 @@ public class ConditionMonitorTest extends SysuiTestCase {
         verify(callback2).onConditionsChanged(true);
     }
 
+    @Test
+    public void addCallback_noConditions_reportAllConditionsMet() {
+        final Monitor monitor = new Monitor(new HashSet<>());
+        final Monitor.Callback callback = mock(Monitor.Callback.class);
+
+        monitor.addCallback(callback);
+
+        verify(callback).onConditionsChanged(true);
+    }
+
     @Test
     public void removeCallback_shouldNoLongerReceiveUpdate() {
         final Monitor.Callback callback =