Make extensions DSE persistent in browser prefs (Reland)

components/search_engines/template_url.h

Index: components/search_engines/template_url.h
diff --git a/components/search_engines/template_url.h b/components/search_engines/template_url.h
index d57aed22627266467d0f47eb6bf5b413c5bbface..ad4d7cc9b117576f23fdb2a1ae84994112eec394 100644
--- a/components/search_engines/template_url.h
+++ b/components/search_engines/template_url.h
@@ -512,6 +512,11 @@ class TemplateURL {
                           const TemplateURLData* data,
                           const SearchTermsData& search_terms_data);
 
+  // Special case for search_terms_replacement_key comparison, because of
+  // its special initialization in TemplateURL constructor.
+  static bool SearchTermsReplacementKeysMatch(const std::string& key1,
+                                              const std::string& key2);
+
   const TemplateURLData& data() const { return data_; }
 
   const base::string16& short_name() const { return data_.short_name(); }
@@ -594,6 +599,10 @@ class TemplateURL {
     extension_info_ = std::move(extension_info);
   }
 
+  const AssociatedExtensionInfo* GetExtensionInfoForTesting() const {
+    return extension_info_.get();
+  }
+
   // Returns true if |url| supports replacement.
   bool SupportsReplacement(const SearchTermsData& search_terms_data) const;