SearchFeatureProvider's context field is removed

SearchFeatureProvider was holding on to a context and
outlived the SettingsActivity, thus leaking the activity.
The context was passed into most methods, and thus it
makes more sense to pass it in to every method.

Bug: 33677967
Test: Run MakeSettingsRoboTests
Change-Id: Ia82f30e7e0b83587b4baeef28e81da6b8e4303fe

src/com/android/settings/search2/SearchFeatureProvider.java

@@ -27,7 +27,7 @@ public interface SearchFeatureProvider {
     /**
      * @return true to use the new version of search
      */
-    boolean isEnabled();
+    boolean isEnabled(Context context);
 
     /**
      * Inserts the Menu items into Settings activity.