MD Settings: clarify "controlled by" logic

chrome/browser/extensions/settings_api_helpers.h

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_SETTINGS_API_HELPERS_H_
 #define CHROME_BROWSER_EXTENSIONS_SETTINGS_API_HELPERS_H_
 
 #include "chrome/common/extensions/manifest_handlers/settings_overrides_handler.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 
 // Returns which extension (if any) is overriding the homepage in a given
 // |browser_context|.
 const Extension* GetExtensionOverridingHomepage(
     content::BrowserContext* browser_context);
 
+// Returns which extension (if any) is overriding the New Tab page in a given
+// |browser_context|.
+const Extension* GetExtensionOverridingNewTabPage(
+    content::BrowserContext* browser_context);
+
 // Returns which extension (if any) is overriding the homepage in a given
 // |browser_context|.
 const Extension* GetExtensionOverridingStartupPages(
     content::BrowserContext* browser_context);
 
 // Returns which extension (if any) is overriding the search engine in a given
 // |browser_context|.
 const Extension* GetExtensionOverridingSearchEngine(
     content::BrowserContext* browser_context);
 
 // Returns which extension (if any) is overriding the proxy in a given
 // |browser_context|.
 const Extension* GetExtensionOverridingProxy(
     content::BrowserContext* browser_context);
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_SETTINGS_API_HELPERS_H_