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

chrome/browser/extensions/api/commands/command_service.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/browser/extensions/api/commands/command_service.h"
 
 #include <vector>
 
 #include "base/lazy_instance.h"
 #include "base/prefs/scoped_user_pref_update.h"
@@ skipping 532 matching lines @@
     AddKeybindingPref(page_action_command->accelerator(),
                       extension->id(),
                       page_action_command->command_name(),
                       false,   // Overwriting not allowed.
                       false);  // Not global.
   }
 }
 
 bool CommandService::CanAutoAssign(const Command &command,
                                    const Extension* extension) {
-  // Media Keys are non-exclusive, so allow auto-assigning them.
-  if (Command::IsMediaKey(command.accelerator()))
-    return true;
-
   // Extensions are allowed to auto-assign updated keys if the user has not
   // changed from the previous value.
   if (IsCommandShortcutUserModified(extension, command.command_name()))
     return false;
 
+  // Media Keys are non-exclusive, so allow auto-assigning them.
+  if (Command::IsMediaKey(command.accelerator()))
+    return true;
+
   if (command.global()) {
     using namespace extensions;
     if (command.command_name() == manifest_values::kBrowserActionCommandEvent ||
         command.command_name() == manifest_values::kPageActionCommandEvent)
       return false;  // Browser and page actions are not global in nature.
 
     if (extension->permissions_data()->HasAPIPermission(
             APIPermission::kCommandsAccessibility))
       return true;
 
@@ skipping 291 matching lines @@
   return true;
 }
 
 template <>
 void
 BrowserContextKeyedAPIFactory<CommandService>::DeclareFactoryDependencies() {
   DependsOn(ExtensionCommandsGlobalRegistry::GetFactoryInstance());
 }
 
 }  // namespace extensions