Bubble expanded view - update header color on uimode and overlay change

Bug:123829494
Test: manual
Change-Id: I1e399f30d61ba0e00a7a39a16995209de8896f2c
diff --git a/packages/SystemUI/src/com/android/systemui/bubbles/BubbleExpandedView.java b/packages/SystemUI/src/com/android/systemui/bubbles/BubbleExpandedView.java
index 856b9d6..e8b346e 100644
--- a/packages/SystemUI/src/com/android/systemui/bubbles/BubbleExpandedView.java
+++ b/packages/SystemUI/src/com/android/systemui/bubbles/BubbleExpandedView.java
@@ -354,6 +354,13 @@
         }
     }
 
+    /**
+     * Update bubble expanded view header when user toggles dark mode.
+     */
+    void updateHeaderColor() {
+        mHeaderView.setBackgroundColor(mContext.getColor(R.attr.colorAccent));
+    }
+
     private void updateHeaderView() {
         mSettingsIcon.setContentDescription(getResources().getString(
                 R.string.bubbles_settings_button_description, mAppName));