Broadcast an intent after turning off Grayscale

Settings will send a broadcast when the user disable Grayscale in
Settings. Also, Settings registers a broadcast receiver to monitor the
status changed of Grayscale.

Bug: 118387886
Test: robotests
Change-Id: I92d1b9adf7a600b4abac943ebbd5a11d02d3d1b8

tests/robotests/src/com/android/settings/homepage/contextualcards/conditional/GrayscaleConditionControllerTest.java

@@ -18,11 +18,13 @@ package com.android.settings.homepage.contextualcards.conditional;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
 import android.content.Context;
+import android.content.Intent;
 import android.hardware.display.ColorDisplayManager;
 
 import org.junit.Before;
@@ -80,4 +82,11 @@ public class GrayscaleConditionControllerTest {
 
         verify(mConditionManager).onConditionChanged();
     }
+
+    @Test
+    public void onActionClick_shouldSendBroadcast() {
+        mController.onActionClick();
+
+        verify(mContext).sendBroadcast(any(Intent.class), any(String.class));
+    }
 }