Media Keys should not count towards the max of four shortcuts per extension.

chrome/common/extensions/command.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/command.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ skipping 362 matching lines @@
       case ui::VKEY_MEDIA_STOP:
         shortcut += values::kKeyMediaStop;
         break;
       default:
         return "";
     }
   }
   return shortcut;
 }
 
+// static
+bool Command::IsMediaKey(const ui::Accelerator& accelerator) {
+  if (accelerator.modifiers() != 0)
+    return false;
+
+  return (accelerator.key_code() == ui::VKEY_MEDIA_NEXT_TRACK ||
+          accelerator.key_code() == ui::VKEY_MEDIA_PREV_TRACK ||
+          accelerator.key_code() == ui::VKEY_MEDIA_PLAY_PAUSE ||
+          accelerator.key_code() == ui::VKEY_MEDIA_STOP);
+}
+
 bool Command::Parse(const base::DictionaryValue* command,
                     const std::string& command_name,
                     int index,
                     base::string16* error) {
   DCHECK(!command_name.empty());
 
   base::string16 description;
   if (IsNamedCommand(command_name)) {
     if (!command->GetString(keys::kDescription, &description) ||
         description.empty()) {
@@ skipping 143 matching lines @@
     // dev and will be removed when we launch.
     static bool stable_or_beta =
         chrome::VersionInfo::GetChannel() >= chrome::VersionInfo::CHANNEL_BETA;
     extension_data->SetBoolean("scope_ui_visible", !stable_or_beta);
   }
 
   return extension_data;
 }
 
 }  // namespace extensions