Make sure manifest specified shortcut for Extension Command can not override the built-in shortcuts.

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 "base/lazy_instance.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/api/commands/commands.h"
@@ skipping 214 matching lines @@
 }
 
 void CommandService::AssignInitialKeybindings(const Extension* extension) {
   const extensions::CommandMap* commands =
       CommandsInfo::GetNamedCommands(extension);
   if (!commands)
     return;
 
   extensions::CommandMap::const_iterator iter = commands->begin();
   for (; iter != commands->end(); ++iter) {
-    AddKeybindingPref(iter->second.accelerator(),
-                      extension->id(),
-                      iter->second.command_name(),
-                      false);  // Overwriting not allowed.
+    if (!ExtensionKeybindingRegistry::IsChromeAccelerator(
+        iter->second.accelerator())) {
+      AddKeybindingPref(iter->second.accelerator(),
+                        extension->id(),
+                        iter->second.command_name(),
+                        false);  // Overwriting not allowed.
+    }
   }
 
   const extensions::Command* browser_action_command =
       CommandsInfo::GetBrowserActionCommand(extension);
   if (browser_action_command) {
-    AddKeybindingPref(browser_action_command->accelerator(),
-                      extension->id(),
-                      browser_action_command->command_name(),
-                      false);  // Overwriting not allowed.
+    if (!ExtensionKeybindingRegistry::IsChromeAccelerator(
+        browser_action_command->accelerator())) {
+      AddKeybindingPref(browser_action_command->accelerator(),
+                        extension->id(),
+                        browser_action_command->command_name(),
+                        false);  // Overwriting not allowed.
+    }
   }
 
   const extensions::Command* page_action_command =
       CommandsInfo::GetPageActionCommand(extension);
   if (page_action_command) {
-    AddKeybindingPref(page_action_command->accelerator(),
-                      extension->id(),
-                      page_action_command->command_name(),
-                      false);  // Overwriting not allowed.
+    if (!ExtensionKeybindingRegistry::IsChromeAccelerator(
+        page_action_command->accelerator())) {
+      AddKeybindingPref(page_action_command->accelerator(),
+                        extension->id(),
+                        page_action_command->command_name(),
+                        false);  // Overwriting not allowed.
+    }
   }
 
   const extensions::Command* script_badge_command =
       CommandsInfo::GetScriptBadgeCommand(extension);
   if (script_badge_command) {
-    AddKeybindingPref(script_badge_command->accelerator(),
-                      extension->id(),
-                      script_badge_command->command_name(),
-                      false);  // Overwriting not allowed.
+    if (!ExtensionKeybindingRegistry::IsChromeAccelerator(
+        script_badge_command->accelerator())) {
+      AddKeybindingPref(script_badge_command->accelerator(),
+                        extension->id(),
+                        script_badge_command->command_name(),
+                        false);  // Overwriting not allowed.
+    }
   }
 }
 
 void CommandService::RemoveKeybindingPrefs(const std::string& extension_id,
                                            const std::string& command_name) {
   DictionaryPrefUpdate updater(profile_->GetPrefs(),
                                prefs::kExtensionCommands);
   DictionaryValue* bindings = updater.Get();
 
   typedef std::vector<std::string> KeysToRemove;
@@ skipping 77 matching lines @@
     return false;
 
   *command = *requested_command;
   if (shortcut_assigned.key_code() != ui::VKEY_UNKNOWN)
     command->set_accelerator(shortcut_assigned);
 
   return true;
 }
 
 }  // namespace extensions