Add an extension bubble explaining which extensions are in dev mode.

extensions/common/switches.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/switches.h"
 
 namespace extensions {
 
 namespace switches {
 
@@ skipping 32 matching lines @@
 
 // The time in milliseconds that an extension event page has between being
 // notified of its impending unload and that unload happening.
 const char kEventPageSuspendingTime[]       = "event-page-unloading-time";
 
 // Enables extensions running scripts on chrome:// URLs.
 // Extensions still need to explicitly request access to chrome:// URLs in the
 // manifest.
 const char kExtensionsOnChromeURLs[] = "extensions-on-chrome-urls";
 
+// Whether to force developer mode extensions highlighting.
+const char kForceDevModeHighlighting[] = "force-dev-mode-highlighting";
+
 // Enables setting global commands through the Extensions Commands API.
 const char kGlobalCommands[] = "global-commands";
 
 // Should we prompt the user before allowing external extensions to install?
 // Default is yes.
 const char kPromptForExternalExtensions[] = "prompt-for-external-extensions";
 
 // Enables or disables extension scripts badges in the location bar.
 const char kScriptBadges[] = "script-badges";
 
 // Enable or diable the "script bubble" icon in the URL bar that tells you how
 // many extensions are running scripts on a page.
 const char kScriptBubble[] = "script-bubble";
 
 // Makes component extensions appear in chrome://settings/extensions.
 const char kShowComponentExtensionOptions[] =
     "show-component-extension-options";
 
 }  // namespace switches
 
 }  // namespace extensions