Add traces for main omnibox providers

components/omnibox/browser/history_url_provider.cc

Index: components/omnibox/browser/history_url_provider.cc
diff --git a/components/omnibox/browser/history_url_provider.cc b/components/omnibox/browser/history_url_provider.cc
index 9361023e1d75907f5bcbc6d6feb0418b94227dad..763522b8ffc6af31bd38a07c78e9b41e287d3437 100644
--- a/components/omnibox/browser/history_url_provider.cc
+++ b/components/omnibox/browser/history_url_provider.cc
@@ -16,6 +16,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "components/bookmarks/browser/bookmark_utils.h"
 #include "components/history/core/browser/history_backend.h"
 #include "components/history/core/browser/history_database.h"
@@ -456,6 +457,7 @@ HistoryURLProvider::HistoryURLProvider(AutocompleteProviderClient* client,
 
 void HistoryURLProvider::Start(const AutocompleteInput& input,
                                bool minimal_changes) {
+  TRACE_EVENT0("omnibox", "HistoryURLProvider::Start");
   // NOTE: We could try hard to do less work in the |minimal_changes| case
   // here; some clever caching would let us reuse the raw matches from the
   // history DB without re-querying.  However, we'd still have to go back to
@@ -841,6 +843,7 @@ void HistoryURLProvider::PromoteMatchesIfNecessary(
 
 void HistoryURLProvider::QueryComplete(
     HistoryURLProviderParams* params_gets_deleted) {
+  TRACE_EVENT0("omnibox", "HistoryURLProvider::QueryComplete");
   // Ensure |params_gets_deleted| gets deleted on exit.
   scoped_ptr<HistoryURLProviderParams> params(params_gets_deleted);