Add a new GetInstance() method for remaining files with singleton classes under chrome/browser.

chrome/browser/gtk/browser_toolbar_gtk.cc

Index: chrome/browser/gtk/browser_toolbar_gtk.cc
diff --git a/chrome/browser/gtk/browser_toolbar_gtk.cc b/chrome/browser/gtk/browser_toolbar_gtk.cc
index a50a372d7c9c43ebb102921834f1220badee2620..ad10e517885bc6910a5e250d098dcf217026dc08 100644
--- a/chrome/browser/gtk/browser_toolbar_gtk.cc
+++ b/chrome/browser/gtk/browser_toolbar_gtk.cc
@@ -329,7 +329,7 @@ bool BrowserToolbarGtk::GetAcceleratorForCommandId(
     int id,
     menus::Accelerator* accelerator) {
   const menus::AcceleratorGtk* accelerator_gtk =
-      Singleton<AcceleratorsGtk>()->GetPrimaryAcceleratorForCommand(id);
+      AcceleratorsGtk::GetInstance()->GetPrimaryAcceleratorForCommand(id);
   if (accelerator_gtk)
     *accelerator = *accelerator_gtk;
   return !!accelerator_gtk;