Fix extension command service to check if user has modified key before overwrite on update.

extensions/common/manifest_constants.cc

 // Copyright 2013 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 "extensions/common/manifest_constants.h"
 
 namespace extensions {
 
 namespace manifest_keys {
 
@@ skipping 209 matching lines @@
 const char kRunAtDocumentStart[] = "document_start";
 const char kRunAtDocumentEnd[] = "document_end";
 const char kRunAtDocumentIdle[] = "document_idle";
 const char kPageActionCommandEvent[] = "_execute_page_action";
 const char kPageActionTypeTab[] = "tab";
 const char kPageActionTypePermanent[] = "permanent";
 const char kScriptBadgeCommandEvent[] = "_execute_script_badge";
 const char kLaunchContainerPanel[] = "panel";
 const char kLaunchContainerTab[] = "tab";
 const char kLaunchContainerWindow[] = "window";
+const char kMediaKeyTestCommand[] = "test_mediakeys_update";
 
 }  // namespace manifest_values
 
 // Extension-related error messages. Some of these are simple patterns, where a
 // '*' is replaced at runtime with a specific value. This is used instead of
 // printf because we want to unit test them and scanf is hard to make
 // cross-platform.
 namespace manifest_errors {
 
 const char kActiveTabPermissionNotGranted[] =
@@ skipping 480 matching lines @@
 const char kWebRequestConflictsWithLazyBackground[] =
     "The 'webRequest' API cannot be used with event pages.";
 #if defined(OS_CHROMEOS)
 const char kIllegalPlugins[] =
     "Extensions cannot install plugins on Chrome OS";
 #endif
 
 }  // namespace manifest_errors
 
 }  // namespace extensions