Initial skeleton for System Indicator API

chrome/browser/extensions/extension_action_manager.h

Index: chrome/browser/extensions/extension_action_manager.h
diff --git a/chrome/browser/extensions/extension_action_manager.h b/chrome/browser/extensions/extension_action_manager.h
index adae7fc6cf3e825fae7d9215f75f69720c645ceb..1cad26de12b6ce8f1d72342ca39faae556e3cc85 100644
--- a/chrome/browser/extensions/extension_action_manager.h
+++ b/chrome/browser/extensions/extension_action_manager.h
@@ -39,6 +39,8 @@ class ExtensionActionManager : public ProfileKeyedService,
   ExtensionAction* GetBrowserAction(
       const extensions::Extension& extension) const;
   ExtensionAction* GetScriptBadge(const extensions::Extension& extension) const;
+  ExtensionAction* GetSystemIndicator(
+      const extensions::Extension& extension) const;
 
  private:
   // Implement content::NotificationObserver.
@@ -56,8 +58,9 @@ class ExtensionActionManager : public ProfileKeyedService,
   mutable ExtIdToActionMap page_actions_;
   mutable ExtIdToActionMap browser_actions_;
   mutable ExtIdToActionMap script_badges_;
+  mutable ExtIdToActionMap system_indicators_;
 };
 
-}
+}  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_ACTION_MANAGER_H_