Add metrics for search engine promo and search widget

components/search_engines/search_engine_type.h

Index: components/search_engines/search_engine_type.h
diff --git a/components/search_engines/search_engine_type.h b/components/search_engines/search_engine_type.h
index f61971487da9e2371c08c7e81a0a18aad8387b29..c19dd0e91cf9834999e246a021f7bc23930567ad 100644
--- a/components/search_engines/search_engine_type.h
+++ b/components/search_engines/search_engine_type.h
@@ -8,6 +8,9 @@
 // Enum to record the user's default search engine choice in UMA.  Add new
 // search engines at the bottom and do not delete from this list, so as not
 // to disrupt UMA data already recorded.
+
+// A Java counterpart will be generated for this enum.
+// GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.search_engines
 enum SearchEngineType {
   // Prepopulated engines.
   SEARCH_ENGINE_UNKNOWN = -1,