Removes --enable-stacked-tab-strip flag (Stacked Tabs)

chrome/browser/ui/browser_view_prefs.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/ui/browser_view_prefs.h"
 
 #include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
 #include "chrome/common/pref_names.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include "ui/base/x/x11_util.h"
 #endif
 
 namespace {
 
 // How long do we wait before we consider a window hung (in ms).
 const int kDefaultPluginMessageResponseTimeout = 25000;
 
 // How frequently we check for hung plugin windows.
 const int kDefaultHungPluginDetectFrequency = 2000;
 
+// DEPRECATED: this is replaced by kTabStripStackedLayout and exists for
+// backwards compatibility.
+// Old values: 0 = SHRINK (default), 1 = STACKED.
+const char kTabStripLayoutType[] = "tab_strip_layout_type";
+
 }  // namespace
 
 namespace chrome {
 
 void RegisterBrowserViewLocalPrefs(PrefRegistrySimple* registry) {
   registry->RegisterIntegerPref(prefs::kPluginMessageResponseTimeout,
                                 kDefaultPluginMessageResponseTimeout);
   registry->RegisterIntegerPref(prefs::kHungPluginDetectFrequency,
                                 kDefaultHungPluginDetectFrequency);
+  registry->RegisterIntegerPref(kTabStripLayoutType, 0);
+  registry->RegisterBooleanPref(prefs::kTabStripStackedLayout, false);
 }
 
 void RegisterBrowserViewProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   bool custom_frame_default = false;
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   custom_frame_default = ui::GetCustomFramePrefDefault();
 #endif
 
   registry->RegisterBooleanPref(
       prefs::kUseCustomChromeFrame,
       custom_frame_default,
       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
 
+void MigrateBrowserTabStripPrefs(PrefService* prefs) {
+  if (prefs->HasPrefPath(kTabStripLayoutType)) {
+    prefs->SetBoolean(prefs::kTabStripStackedLayout,
+                      prefs->GetInteger(kTabStripLayoutType) != 0);
+    prefs->ClearPref(kTabStripLayoutType);
+  }
+}
+
 }  // namespace chrome