Move physical keyboard search landing page to its Fragment

This CL moves the code building index of physical keyboards from
InputMethodAndLanguageSettings to PhysicalKeyboardFragment, so that a
search landing page becomes PhysicalKeyboardFragment as expected.

Bug: 32643633
Test: Connecting/Disconnecting Anker bluetooth keyboard while Settings
      app is/isn't running, the search Anker and verify landing page
      is PhysicalKeyboardFragment.
Test: Update robolectric DynamicIndexableContentMonitorTest.

Change-Id: I51f308ada74966a96c258f8ef50a9b4fc7bc6635
diff --git a/src/com/android/settings/search/SearchIndexableResources.java b/src/com/android/settings/search/SearchIndexableResources.java
index 4ecbcf1..e1b7fd7 100644
--- a/src/com/android/settings/search/SearchIndexableResources.java
+++ b/src/com/android/settings/search/SearchIndexableResources.java
@@ -55,6 +55,7 @@
 import com.android.settings.gestures.PickupGestureSettings;
 import com.android.settings.gestures.SwipeToNotificationSettings;
 import com.android.settings.inputmethod.InputMethodAndLanguageSettings;
+import com.android.settings.inputmethod.PhysicalKeyboardFragment;
 import com.android.settings.location.LocationSettings;
 import com.android.settings.location.ScanningSettings;
 import com.android.settings.network.NetworkDashboardFragment;
@@ -141,6 +142,7 @@
                 R.drawable.ic_settings_accounts);
         addIndex(InputMethodAndLanguageSettings.class,
                 NO_DATA_RES_ID, R.drawable.ic_settings_language);
+        addIndex(PhysicalKeyboardFragment.class, NO_DATA_RES_ID, R.drawable.ic_settings_language);
         addIndex(PrivacySettings.class, NO_DATA_RES_ID, R.drawable.ic_settings_backup);
         addIndex(DateTimeSettings.class, NO_DATA_RES_ID, R.drawable.ic_settings_date_time);
         addIndex(AccessibilitySettings.class, NO_DATA_RES_ID, R.drawable.ic_settings_accessibility);