Adding warmup call API for Settings search ranking.

- This allows the ranking implementations to prepare for predictions and
avoids latency on the first prediction call.

Bug: 38197948
Bug: 37312700

Test: RunSettingsRoboTests

Change-Id: I1878b14765ad7cede5648fa1c7f29c419c2e5535

src/com/android/settings/search/SearchFeatureProvider.java

@@ -130,4 +130,10 @@ public interface SearchFeatureProvider {
         return false;
     }
 
+    /**
+     * Prepare for search ranking predictions to avoid latency on the first prediction call.
+     */
+    default void searchRankingWarmup(Context context) {
+    }
+
 }

src/com/android/settings/search/SearchFragment.java

@@ -209,6 +209,10 @@ public class SearchFragment extends InstrumentedFragment implements SearchView.O
     @Override
     public void onResume() {
         super.onResume();
+        Context appContext = getContext().getApplicationContext();
+        if (mSearchFeatureProvider.isSmartSearchRankingEnabled(appContext)) {
+            mSearchFeatureProvider.searchRankingWarmup(appContext);
+        }
         requery();
     }
 

tests/robotests/src/com/android/settings/search/SearchFragmentTest.java

@@ -451,6 +451,36 @@ public class SearchFragmentTest {
                 nullable(String.class), eq(searchResult));
     }
 
+    @Test
+    public void onResume_shouldCallSearchRankingWarmupIfSmartSearchRankingEnabled(){
+        when(mFeatureFactory.searchFeatureProvider.isSmartSearchRankingEnabled(any(Context.class)))
+                .thenReturn(true);
+
+        ActivityController<SearchActivity> activityController =
+                Robolectric.buildActivity(SearchActivity.class);
+        activityController.setup();
+        SearchFragment fragment = (SearchFragment) activityController.get().getFragmentManager()
+                .findFragmentById(R.id.main_content);
+
+        verify(mFeatureFactory.searchFeatureProvider)
+                .searchRankingWarmup(any(Context.class));
+    }
+
+    @Test
+    public void onResume_shouldNotCallSearchRankingWarmupIfSmartSearchRankingDisabled(){
+        when(mFeatureFactory.searchFeatureProvider.isSmartSearchRankingEnabled(any(Context.class)))
+                .thenReturn(false);
+
+        ActivityController<SearchActivity> activityController =
+                Robolectric.buildActivity(SearchActivity.class);
+        activityController.setup();
+        SearchFragment fragment = (SearchFragment) activityController.get().getFragmentManager()
+                .findFragmentById(R.id.main_content);
+
+        verify(mFeatureFactory.searchFeatureProvider, never())
+                .searchRankingWarmup(any(Context.class));
+    }
+
     private ArgumentMatcher<Pair<Integer, Object>> pairMatches(int tag) {
         return pair -> pair.first == tag;
     }