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

chrome/browser/ui/cocoa/tab_view.mm

Index: chrome/browser/ui/cocoa/tab_view.mm
diff --git a/chrome/browser/ui/cocoa/tab_view.mm b/chrome/browser/ui/cocoa/tab_view.mm
index 58659ca67905dcb9d4d81ed119e9d3e67823c12f..aa043db48eb80f7cd7deccb4fce50a675f3bf273 100644
--- a/chrome/browser/ui/cocoa/tab_view.mm
+++ b/chrome/browser/ui/cocoa/tab_view.mm
@@ -80,7 +80,7 @@ const CGFloat kRapidCloseDist = 2.5;
   // TODO(dtseng): crbug.com/59978.
   // Retain in case we remove it from its superview.
   closeButtonRetainer_.reset([closeButton_ retain]);
-  if (Singleton<BrowserAccessibilityState>::get()->IsAccessibleBrowser()) {
+  if (BrowserAccessibilityState::GetInstance()->IsAccessibleBrowser()) {
     // The superview gives up ownership of the closeButton here.
     [closeButton_ removeFromSuperview];
   }