Add bookmark entry point histogram for bookmark prompt experiment

chrome/browser/ui/views/frame/browser_view.cc

Index: chrome/browser/ui/views/frame/browser_view.cc
diff --git a/chrome/browser/ui/views/frame/browser_view.cc b/chrome/browser/ui/views/frame/browser_view.cc
index b10999d50311c864d81719c0d2cc5a1a7ef23f88..a37788c9bb010a5d4cc0e6b6498aa897bba6dcca 100644
--- a/chrome/browser/ui/views/frame/browser_view.cc
+++ b/chrome/browser/ui/views/frame/browser_view.cc
@@ -2403,6 +2403,11 @@ void BrowserView::UpdateAcceleratorMetrics(
   if (command_id == IDC_HELP_PAGE_VIA_KEYBOARD && key_code == ui::VKEY_F1)
     content::RecordAction(UserMetricsAction("ShowHelpTabViaF1"));
 
+  if (command_id == IDC_BOOKMARK_PAGE)
+    UMA_HISTOGRAM_ENUMERATION("Bookmarks.EntryPoint",
+                              bookmark_utils::ENTRY_POINT_ACCELERATOR,
+                              bookmark_utils::ENTRY_POINT_LIMIT);
+
 #if defined(OS_CHROMEOS)
   // Collect information about the relative popularity of various accelerators
   // on Chrome OS.