Removing iPad Tab Switcher experimental flag.

ios/chrome/app/main_controller.mm

Index: ios/chrome/app/main_controller.mm
diff --git a/ios/chrome/app/main_controller.mm b/ios/chrome/app/main_controller.mm
index 3aaa1d91363c5c936aa907bfb632ad2e3af81169..fa2f5539b3cdcb6a4837f8f32134481a27097d6a 100644
--- a/ios/chrome/app/main_controller.mm
+++ b/ios/chrome/app/main_controller.mm
@@ -534,8 +534,6 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
 // Initializes the application to INITIALIZATION_STAGE_FOREGROUND, which is
 // needed when application runs in foreground.
 - (void)startUpBrowserForegroundInitialization;
-// Swaps the UI between Incognito and normal modes.
-- (void)swapBrowserModes;
 @end
 
 @implementation MainController
@@ -820,17 +818,13 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
 - (void)deleteIncognitoBrowserState {
   BOOL otrBVCIsCurrent = (self.currentBVC == self.otrBVC);
 
-  const BOOL isOnIPadWithTabSwitcherEnabled =
-      IsIPadIdiom() && experimental_flags::IsTabSwitcherEnabled();
-
   // If the current BVC is the otr BVC, then the user should be in the card
   // stack, this is not true for the iPad tab switcher.
-  DCHECK(isOnIPadWithTabSwitcherEnabled ||
-         (!otrBVCIsCurrent || _tabSwitcherIsActive));
+  DCHECK(IsIPadIdiom() || (!otrBVCIsCurrent || _tabSwitcherIsActive));
 
   // We always clear the otr tab model on iPad.
   // Notify the _tabSwitcherController that its otrBVC will be destroyed.
-  if (isOnIPadWithTabSwitcherEnabled || _tabSwitcherIsActive)
+  if (IsIPadIdiom() || _tabSwitcherIsActive)
     [_tabSwitcherController setOtrTabModel:nil];
 
   [_browserViewWrangler
@@ -842,7 +836,7 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
 
   // Always set the new otr tab model on iPad with tab switcher enabled.
   // Notify the _tabSwitcherController with the new otrBVC.
-  if (isOnIPadWithTabSwitcherEnabled || _tabSwitcherIsActive)
+  if (IsIPadIdiom() || _tabSwitcherIsActive)
     [_tabSwitcherController setOtrTabModel:self.otrTabModel];
 }
 
@@ -1442,10 +1436,6 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
     case IDC_OPEN_URL:
       [self openUrl:base::mac::ObjCCast<OpenUrlCommand>(sender)];
       break;
-    case IDC_SWITCH_BROWSER_MODES:
-      DCHECK(IsIPadIdiom());
-      [self swapBrowserModes];
-      break;
     case IDC_OPTIONS:
       [self showSettings];
       break;
@@ -1484,8 +1474,7 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
       break;
     case IDC_TOGGLE_TAB_SWITCHER:
       DCHECK(!_tabSwitcherIsActive);
-      if ((!IsIPadIdiom() || experimental_flags::IsTabSwitcherEnabled()) &&
-          !_isProcessingVoiceSearchCommand) {
+      if (!_isProcessingVoiceSearchCommand) {
         [self showTabSwitcher];
         _isProcessingTabSwitcherCommand = YES;
         dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
@@ -1702,12 +1691,7 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
   }
 
   if (IsIPadIdiom()) {
-    if (experimental_flags::IsTabSwitcherEnabled()) {
-      [self showTabSwitcher];
-    } else {
-      // Mode switch if not in regular mode.
-      [self swapBrowserModes];
-    }
+    [self showTabSwitcher];
   } else {
     self.currentBVC = self.mainBVC;
     if ([self.currentTabModel count] == 0U) {
@@ -1727,13 +1711,7 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
     return;
   }
 
-  if (IsIPadIdiom()) {
-    if (experimental_flags::IsTabSwitcherEnabled()) {
-      [self showTabSwitcher];
-    }
-  } else {
-    [self showTabSwitcher];
-  }
+  [self showTabSwitcher];
 }
 
 #pragma mark - Mode Switching
@@ -1775,17 +1753,6 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
   return self.currentBVC.browserState;
 }
 
-- (void)swapBrowserModes {
-  if (self.mainBVC == self.currentBVC)
-    self.currentBVC = self.otrBVC;
-  else
-    self.currentBVC = self.mainBVC;
-  // Make sure there is at least one tab open.
-  if ([self shouldOpenNTPTabOnActivationOfTabModel:[self currentTabModel]])
-    [self.currentBVC newTab:nil];
-  [_browserViewWrangler updateModeToggle];
-}
-
 // NOTE: If you change this function, it may have an effect on the performance
 // of opening the stack view. Please make sure you also change the corresponding
 // code in StackViewControllerPerfTest::MainControllerShowTabSwitcher().
@@ -1804,8 +1771,7 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
     [currentTab setSnapshotCoalescingEnabled:NO];
   }));
 
-  if (experimental_flags::IsTabSwitcherEnabled())
-    [currentBVC prepareToEnterTabSwitcher:nil];
+  [currentBVC prepareToEnterTabSwitcher:nil];
 
   if (!_tabSwitcherController.get()) {
     if (IsIPadIdiom()) {
@@ -1831,7 +1797,7 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
   }
   _tabSwitcherIsActive = YES;
   [_tabSwitcherController setDelegate:self];
-  if (IsIPadIdiom() && experimental_flags::IsTabSwitcherEnabled()) {
+  if (IsIPadIdiom()) {
     TabSwitcherTransitionContext* transitionContext =
         [TabSwitcherTransitionContext
             tabSwitcherTransitionContextWithCurrent:currentBVC
@@ -1914,7 +1880,6 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
 }
 
 - (void)beginDismissingStackViewWithCurrentModel:(TabModel*)tabModel {
-  DCHECK(experimental_flags::IsTabSwitcherEnabled() || !IsIPadIdiom());
   DCHECK(tabModel == self.mainTabModel || tabModel == self.otrTabModel);
 
   _dismissingStackView = YES;
@@ -1927,7 +1892,6 @@ enum class StackViewDismissalMode { NONE, NORMAL, INCOGNITO };
 }
 
 - (void)finishDismissingStackView {
-  DCHECK(!IsIPadIdiom() || experimental_flags::IsTabSwitcherEnabled());
   DCHECK_EQ(self.mainViewController.activeViewController,
             _tabSwitcherController.get());