[Panel refactor] use browserless Panels by default in Dev/Canary

chrome/browser/extensions/api/tabs/tabs.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/tabs/tabs.h"
 
 #include <algorithm>
 #include <limits>
 #include <vector>
 
@@ skipping 557 matching lines @@
         error_ = keys::kInvalidWindowTypeError;
         return false;
       }
     }
   }
 
   if (window_type == Browser::TYPE_PANEL) {
     std::string title =
         web_app::GenerateApplicationNameFromExtensionId(extension_id);
 #if !defined(USE_ASH)
-    if (CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kBrowserlessPanels)) {
+    if (PanelManager::UseBrowserlessPanels()) {
       // Note: Panels ignore all but the first url provided.
       Panel* panel = PanelManager::GetInstance()->CreatePanel(
           title, window_profile, urls[0], panel_bounds.size());
 
       // Unlike other window types, Panels do not take focus by default.
       if (!saw_focus_key || !focused)
         panel->ShowInactive();
       else
         panel->Show();
 
@@ skipping 1230 matching lines @@
   // called for every API call the extension made.
   GotLanguage(language);
 }
 
 void DetectTabLanguageFunction::GotLanguage(const std::string& language) {
   SetResult(Value::CreateStringValue(language.c_str()));
   SendResponse(true);
 
   Release();  // Balanced in Run()
 }