Remove search::GetSearchTerms since it always returns empty string

chrome/common/search/search_types.h

Index: chrome/common/search/search_types.h
diff --git a/chrome/common/search/search_types.h b/chrome/common/search/search_types.h
index 6a444e13a96c85cccbf03a18b4f0d5bae798d870..4da3ad99276e538ea86fda6128812d13c3021081 100644
--- a/chrome/common/search/search_types.h
+++ b/chrome/common/search/search_types.h
@@ -20,6 +20,7 @@ struct SearchMode {
     MODE_SEARCH_SUGGESTIONS,
 
     // On a search results page.
+    // TODO(treib): Remove this; it's not used anymore. crbug.com/627747
     MODE_SEARCH_RESULTS,
   };
 
@@ -32,6 +33,7 @@ struct SearchMode {
     ORIGIN_NTP,
 
     // The user is searching from a search results page.
+    // TODO(treib): Remove this; it's not used anymore. crbug.com/627747
     ORIGIN_SEARCH,
   };