Revert of Enable the iPad Tab Switcher by default.

ios/chrome/browser/experimental_flags.mm

 // Copyright 2015 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.
 
 // This file can be empty. Its purpose is to contain the relatively short lived
 // definitions required for experimental flags.
 
 #include "ios/chrome/browser/experimental_flags.h"
 
 #include <dispatch/dispatch.h>
@@ skipping 69 matching lines @@
   if ([[NSUserDefaults standardUserDefaults]
           boolForKey:kHeuristicsForPasswordGeneration]) {
     return true;
   }
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   return command_line->HasSwitch(
       autofill::switches::kLocalHeuristicsOnlyForPasswordGeneration);
 }
 
 bool IsTabSwitcherEnabled() {
-  // Check if the experimental flag is forced off.
+  // Check if the experimental flag is forced on or off.
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kDisableTabSwitcher)) {
+  if (command_line->HasSwitch(switches::kEnableTabSwitcher)) {
+    return true;
+  } else if (command_line->HasSwitch(switches::kDisableTabSwitcher)) {
     return false;
   }
 
-  // Check if the finch experiment is turned off.
+  // Check if the finch experiment is turned on.
   std::string group_name = base::FieldTrialList::FindFullName("IOSTabSwitcher");
-  return !base::StartsWith(group_name, "Disabled",
-                           base::CompareCase::INSENSITIVE_ASCII);
+  return base::StartsWith(group_name, "Enabled",
+                          base::CompareCase::INSENSITIVE_ASCII);
 }
 
 bool IsReadingListEnabled() {
   return [[NSUserDefaults standardUserDefaults] boolForKey:kEnableReadingList];
 }
 
 bool IsAllBookmarksEnabled() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kEnableAllBookmarksView)) {
     return true;
@@ skipping 68 matching lines @@
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   return !command_line->HasSwitch(switches::kDisableSpotlightActions);
 }
 
 bool IsMDMIntegrationEnabled() {
   return ![[NSUserDefaults standardUserDefaults]
       boolForKey:kMDMIntegrationDisabled];
 }
 
 }  // namespace experimental_flags