Move GoogleImageSearchSource() from template_url.cc to UIThreadSearchTermsData

components/search_engines/search_terms_data.cc

Index: components/search_engines/search_terms_data.cc
diff --git a/components/search_engines/search_terms_data.cc b/components/search_engines/search_terms_data.cc
index f94b205f9c0ecee4e4324c11b3963212f082d870..c6c72ba2060b267312df588c90dcddfc0f10adcb 100644
--- a/components/search_engines/search_terms_data.cc
+++ b/components/search_engines/search_terms_data.cc
@@ -61,3 +61,7 @@ std::string SearchTermsData::GetSuggestRequestIdentifier() const {
 std::string SearchTermsData::NTPIsThemedParam() const {
   return std::string();
 }
+
+std::string SearchTermsData::GoogleImageSearchSource() const {
+  return std::string();
+}