Fix issue where theme would be accepted in SUW

An event passing null would cause the internal state of
ThemeOverlayController to be reset, accepting future theming events.

Test: atest ThemeOverlayControllerTest
Bug: 182560740
Change-Id: Ie619ff5ae73b97e6a26cc90227bcad1c6277b30b

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

@@ -151,6 +151,10 @@ public class ThemeOverlayController extends SystemUI implements Dumpable {
                         + wallpaperColors);
                 mDeferredThemeEvaluation = true;
                 return;
+            } else if (mDeferredThemeEvaluation) {
+                Log.i(TAG, "Wallpaper color event received, but we already were deferring eval: "
+                        + wallpaperColors);
+                return;
             } else {
                 if (DEBUG) {
                     Log.i(TAG, "During user setup, but allowing first color event: had? "

packages/SystemUI/tests/src/com/android/systemui/theme/ThemeOverlayControllerTest.java

@@ -212,6 +212,18 @@ public class ThemeOverlayControllerTest extends SysuiTestCase {
         mColorsListener.getValue().onColorsChanged(mainColors, WallpaperManager.FLAG_SYSTEM);
 
         verify(mThemeOverlayApplier).applyCurrentUserOverlays(any(), any(), anyInt(), any());
+
+        // Regression test: null events should not reset the internal state and allow colors to be
+        // applied again.
+        clearInvocations(mThemeOverlayApplier);
+        mBroadcastReceiver.getValue().onReceive(null, new Intent(Intent.ACTION_WALLPAPER_CHANGED));
+        mColorsListener.getValue().onColorsChanged(null, WallpaperManager.FLAG_SYSTEM);
+        verify(mThemeOverlayApplier, never()).applyCurrentUserOverlays(any(), any(), anyInt(),
+                any());
+        mColorsListener.getValue().onColorsChanged(new WallpaperColors(Color.valueOf(Color.GREEN),
+                null, null), WallpaperManager.FLAG_SYSTEM);
+        verify(mThemeOverlayApplier, never()).applyCurrentUserOverlays(any(), any(), anyInt(),
+                any());
     }
 
     @Test