Delete from Sync the artificial search engines created by the omnibox extensions.

components/search_engines/template_url_service_client.h

Index: components/search_engines/template_url_service_client.h
diff --git a/components/search_engines/template_url_service_client.h b/components/search_engines/template_url_service_client.h
index 46147aee3982973bdcd80b53decb7327f08cf6d4..734ce2423ff13ba752039f91e50abb0da7987b61 100644
--- a/components/search_engines/template_url_service_client.h
+++ b/components/search_engines/template_url_service_client.h
@@ -37,8 +37,8 @@ class TemplateURLServiceClient {
   // Adds the given URL to history as a keyword generated visit.
   virtual void AddKeywordGeneratedVisit(const GURL& url) = 0;
 
-  // Restores the extension info of a TemplateURL loaded from the database.
-  virtual void RestoreExtensionInfoIfNecessary(TemplateURL* template_url) = 0;
+  // Returns true iff |url| has "chrome-extension" scheme.

[Peter Kasting, 2016/10/05 00:15:21]

Nit: Technically this description is a layering violation; it is how the
Chrome-side implementation works, but on the component side, we shouldn't
theoretically know about schemes like this.

Maybe instead say something like: "Given the main search |url| for a
TemplateURL, returns whether the TemplateURL is from an omnibox extension."

[vasilii, 2016/10/05 12:03:48]

Done.

+  virtual bool IsOmniboxExtensionURL(const std::string& url) = 0;
 };
 
 #endif  // COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_CLIENT_H_