Added the Ash.Tab.TimeBetweenSwitchToExistingTabUserActions histogram to track time between tab swit

chrome/browser/ui/browser_commands.cc

Index: chrome/browser/ui/browser_commands.cc
diff --git a/chrome/browser/ui/browser_commands.cc b/chrome/browser/ui/browser_commands.cc
index 90e6be26a667bd490229e8390daea3476e443267..3bd3ea7357d47199a0904c594c821d342173436c 100644
--- a/chrome/browser/ui/browser_commands.cc
+++ b/chrome/browser/ui/browser_commands.cc
@@ -543,6 +543,7 @@ void NewTab(Browser* browser) {
   // user-initiated commands.
   UMA_HISTOGRAM_ENUMERATION("Tab.NewTab", TabStripModel::NEW_TAB_COMMAND,
                             TabStripModel::NEW_TAB_ENUM_COUNT);
+  // TODO(bruthig):
 
   if (browser->is_type_tabbed()) {
     AddTabAt(browser, GURL(), -1, true);
@@ -620,6 +621,7 @@ void SelectNumberedTab(Browser* browser, int index) {
   if (index < browser->tab_strip_model()->count()) {
     content::RecordAction(UserMetricsAction("SelectNumberedTab"));
     browser->tab_strip_model()->ActivateTabAt(index, true);
+    // TODO(bruthig):
   }
 }