Add shadow to searchbar when user scrolls vertically

Bug: 63528057
Test: robotests

Change-Id: Ib85676d78b43be38aab1eacd0820d0755a601f60

src/com/android/settings/dashboard/DashboardSummary.java

@@ -40,6 +40,7 @@ import com.android.settings.dashboard.suggestions.SuggestionDismissController;
 import com.android.settings.dashboard.suggestions.SuggestionFeatureProvider;
 import com.android.settings.dashboard.suggestions.SuggestionsChecks;
 import com.android.settings.overlay.FeatureFactory;
+import com.android.settings.widget.ActionBarShadowController;
 import com.android.settingslib.drawer.CategoryKey;
 import com.android.settingslib.drawer.DashboardCategory;
 import com.android.settingslib.drawer.SettingsDrawerActivity;
@@ -193,12 +194,14 @@ public class DashboardSummary extends InstrumentedFragment
         mDashboard.setLayoutManager(mLayoutManager);
         mDashboard.setHasFixedSize(true);
         mDashboard.setListener(this);
-        Log.d(TAG, "adapter created");
         mAdapter = new DashboardAdapter(getContext(), bundle, mConditionManager.getConditions(),
             mSuggestionParser, this /* SuggestionDismissController.Callback */);
         mDashboard.setAdapter(mAdapter);
         mDashboard.setItemAnimator(new DashboardItemAnimator());
         mSummaryLoader.setSummaryConsumer(mAdapter);
+        ActionBarShadowController.attachToRecyclerView(
+                getActivity().findViewById(R.id.search_bar_container), getLifecycle(), mDashboard);
+
         if (DEBUG_TIMING) {
             Log.d(TAG, "onViewCreated took "
                     + (System.currentTimeMillis() - startTime) + " ms");