Allow overlays to be notified about theme changes

Overlays should override onOverlaysApplied() in order to act upon theme
changes.

Test: manual
Bug: 190093578
Change-Id: Ie52b8c55a046d150dd30aae5fabb279b53a959f5

packages/SystemUI/src/com/android/systemui/dump/DumpManager.kt

@@ -34,7 +34,7 @@ import javax.inject.Inject
  * See [DumpHandler] for more information on how and when this information is dumped.
  */
 @SysUISingleton
-class DumpManager @Inject constructor() {
+open class DumpManager @Inject constructor() {
     private val dumpables: MutableMap<String, RegisteredDumpable<Dumpable>> = ArrayMap()
     private val buffers: MutableMap<String, RegisteredDumpable<LogBuffer>> = ArrayMap()
 

packages/SystemUI/src/com/android/systemui/flags/SystemPropertiesHelper.kt

@@ -25,8 +25,12 @@ import javax.inject.Inject
  * Proxy to make {@link SystemProperties} easily testable.
  */
 @SysUISingleton
-class SystemPropertiesHelper @Inject constructor() {
+open class SystemPropertiesHelper @Inject constructor() {
     fun getBoolean(name: String, default: Boolean): Boolean {
         return SystemProperties.getBoolean(name, default)
     }
+
+    fun set(name: String, value: Int) {
+        SystemProperties.set(name, value.toString())
+    }
 }

packages/SystemUI/src/com/android/systemui/theme/ThemeOverlayController.java

@@ -535,6 +535,10 @@ public class ThemeOverlayController extends SystemUI implements Dumpable {
             mThemeManager.applyCurrentUserOverlays(categoryToPackage, null, currentUser,
                     managedProfiles);
         }
+        onOverlaysApplied();
+    }
+
+    protected void onOverlaysApplied() {
     }
 
     @Override