Revert of Enable the iPad Tab Switcher by default.

ios/chrome/browser/experimental_flags.mm

Index: ios/chrome/browser/experimental_flags.mm
diff --git a/ios/chrome/browser/experimental_flags.mm b/ios/chrome/browser/experimental_flags.mm
index 4069bd48c5e8b76dc2ff2d0820c481e99414acaa..32975b428b551f88c4fe9d568ea67d18d89c5f43 100644
--- a/ios/chrome/browser/experimental_flags.mm
+++ b/ios/chrome/browser/experimental_flags.mm
@@ -87,16 +87,18 @@
 }
 
 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() {