Migrate from Plugin SearchTarget to API search Target [3/3]

- Implement SearchServicePipeline which utilizes system Search services for AllAppsSearch Results
- Parse android.app.search.SearchTarget handling for Shortcut, Slice, Settings and Play results
- Aggregate SearchTargets to a tree structure for in-line Search Results

Bug: 177223401
Test: Manual
Change-Id: Iddc0f3691578fd332cd2df643a237b29f3eccd0d

quickstep/src/com/android/launcher3/search/SearchTargetHandler.java

@@ -20,6 +20,8 @@ import android.app.search.SearchTarget;
 
 import com.android.systemui.plugins.shared.SearchTargetLegacy;
 
+import java.util.List;
+
 /**
  * An interface for supporting dynamic search results
  */
@@ -28,13 +30,14 @@ public interface SearchTargetHandler {
     /**
      * Update view using values from {@link SearchTargetLegacy}
      */
-    void applySearchTarget(SearchTargetLegacy searchTarget);
+    default void applySearchTarget(SearchTargetLegacy searchTarget) {
+    }
+
 
     /**
      * Update view using values from {@link SearchTargetLegacy}
      */
-    default void applySearchTarget(SearchTarget searchTarget){
-
+    default void applySearchTarget(SearchTarget parentTarget, List<SearchTarget> children) {
     }
 
     /**