Make extensions DSE persistent in browser prefs

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 77a22d26706f4ec8eeacf490f5212713a4ff6f4f..7ba2746b9596b6e108a24a6f86977e6d8b9fcdb1 100644
--- a/components/search_engines/template_url_service_client.h
+++ b/components/search_engines/template_url_service_client.h
@@ -40,6 +40,10 @@ class TemplateURLServiceClient {
   // Given the main search |url| for a TemplateURL, returns whether the
   // TemplateURL is from an omnibox extension.
   virtual bool IsOmniboxExtensionURL(const std::string& url) = 0;
+
+  // Returns extension id for extension that is currently overriding default
+  // search preference.
+  virtual std::string GetExtensionControllingDSEPref() = 0;

[vasilii, 2016/12/06 19:16:42]

Hopefully, you won't need it. The component should know better the current
state. 

[Alexander Yashkin, 2016/12/09 08:19:52]

I have written my thoughts above, not sure we can get without it.

 };
 
 #endif  // COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_CLIENT_H_