Remove getCategoryKey() from DashboardFragment children.

Use the centralized registry to look up category key instead.

Bug: 32936784
Test: make RunSettingsRoboTests -j40
Change-Id: I0b8c72d70f93e4b5c58871ac90de41f69ad15653

tests/robotests/src/com/android/settings/accounts/AccountDetailDashboardFragmentTest.java

@@ -82,7 +82,8 @@ public class AccountDetailDashboardFragmentTest {
 
     @Test
     public void testCategory_isAccount() {
-        assertThat(mFragment.getCategoryKey()).isEqualTo(CategoryKey.CATEGORY_ACCOUNT);
+        assertThat(new AccountDetailDashboardFragment().getCategoryKey())
+                .isEqualTo(CategoryKey.CATEGORY_ACCOUNT);
     }
 
     @Test

tests/robotests/src/com/android/settings/dashboard/DashboardFragmentTest.java

@@ -26,7 +26,6 @@ import com.android.settings.TestConfig;
 import com.android.settings.core.PreferenceController;
 import com.android.settings.overlay.FeatureFactory;
 import com.android.settings.testutils.FakeFeatureFactory;
-import com.android.settingslib.drawer.CategoryKey;
 import com.android.settingslib.drawer.DashboardCategory;
 import com.android.settingslib.drawer.Tile;
 
@@ -199,11 +198,6 @@ public class DashboardFragmentTest {
             return 0;
         }
 
-        @Override
-        protected String getCategoryKey() {
-            return CategoryKey.CATEGORY_HOMEPAGE;
-        }
-
         @Override
         public PreferenceScreen getPreferenceScreen() {
             return mScreen;

tests/robotests/src/com/android/settings/network/NetworkDashboardFragmentTest.java

@@ -21,6 +21,7 @@ import android.provider.SearchIndexableResource;
 import com.android.settings.SettingsRobolectricTestRunner;
 import com.android.settings.TestConfig;
 import com.android.settings.accounts.UserAndAccountDashboardFragment;
+import com.android.settings.dashboard.DashboardFragmentRegistry;
 import com.android.settings.testutils.FakeFeatureFactory;
 import com.android.settingslib.drawer.CategoryKey;
 import org.junit.Before;