Fix TemplateUrl::MatchesData comparison of search_terms_replacement_key (reland)

components/search_engines/default_search_manager.h

Index: components/search_engines/default_search_manager.h
diff --git a/components/search_engines/default_search_manager.h b/components/search_engines/default_search_manager.h
index aadc6a4648952a740881931ea7ac2c7fed629882..7d959b37b759707999142c21c2db089be1976967 100644
--- a/components/search_engines/default_search_manager.h
+++ b/components/search_engines/default_search_manager.h
@@ -63,9 +63,15 @@ class DefaultSearchManager {
   static const char kDisabledByPolicy[];
 
   enum Source {
+    // Default search engine chosen either from prepopulated engines set for
+    // current country or overriden from kSearchProviderOverrides preference.
     FROM_FALLBACK = 0,
+    // User selected engine.
     FROM_USER,
+    // Search engine set by extension overriding default search.
     FROM_EXTENSION,
+    // Search engine controlled externally through enterprise configuration
+    // management (e.g. windows group policy).
     FROM_POLICY,
   };