Add new permission string for extensions that override new tab pages.

chrome/common/extensions/chrome_manifest_url_handlers.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/common/extensions/chrome_manifest_url_handlers.h"
 
 #include <memory>
 
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
@@ skipping 124 matching lines @@
       }
       extension->AddWebExtentPattern(pattern);
     }
   }
 
   // An extension may override at most one page.
   if (overrides->size() > 1) {
     *error = base::ASCIIToUTF16(errors::kMultipleOverrides);
     return false;
   }
+
+  // If this is an NTP override extension, add the NTP override permission.
+  if (url_overrides->chrome_url_overrides_.count(chrome::kChromeUINewTabHost)) {
+    PermissionsParser::AddAPIPermission(extension,
+                                        APIPermission::kNewTabPageOverride);
+  }
+
   extension->SetManifestData(keys::kChromeURLOverrides,
                              std::move(url_overrides));
+
   return true;
 }
 
 bool URLOverridesHandler::Validate(
     const Extension* extension,
     std::string* error,
     std::vector<InstallWarning>* warnings) const {
   const URLOverrides::URLOverrideMap& overrides =
       URLOverrides::GetChromeURLOverrides(extension);
   if (overrides.empty())
@@ skipping 11 matching lines @@
     }
   }
   return true;
 }
 
 const std::vector<std::string> URLOverridesHandler::Keys() const {
   return SingleKey(keys::kChromeURLOverrides);
 }
 
 }  // namespace extensions