Make TemplateUrlServiceFactory.Natives public to allow mocking

BUG=1023566

Change-Id: Ie4ea9b81a70f5a383a2b5f486919d9a17cd909c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1917467
Commit-Queue: Pavel Yatsuk <pavely@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715902}

chrome/android/java/src/org/chromium/chrome/browser/search_engines/TemplateUrlServiceFactory.java

@@ -42,8 +42,10 @@ public class TemplateUrlServiceFactory {
         return TemplateUrlServiceFactoryJni.get().doesDefaultSearchEngineHaveLogo();
     }
 
+    // Natives interface is public to allow mocking in tests outside of
+    // org.chromium.chrome.browser.search_engines package.
     @NativeMethods
-    interface Natives {
+    public interface Natives {
         TemplateUrlService getTemplateUrlService();
         boolean doesDefaultSearchEngineHaveLogo();
     }