Disables Native App Launcher functionality.

ios/chrome/browser/tabs/tab.mm

 // Copyright 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.
 
 #import "ios/chrome/browser/tabs/tab.h"
 
 #import <CoreLocation/CoreLocation.h>
 #import <UIKit/UIKit.h>
 
 #include <utility>
@@ skipping 488 matching lines @@
 
     [self updateLastVisitedTimestamp];
     [[self webController] addObserver:self];
     [[self webController] setDelegate:self];
 
     snapshotManager_.reset([[SnapshotManager alloc] init]);
     webControllerSnapshotHelper_.reset([[WebControllerSnapshotHelper alloc]
         initWithSnapshotManager:snapshotManager_
                             tab:self]);
 
-    [self initNativeAppNavigationController];
+    if (experimental_flags::IsNativeAppLauncherEnabled())
+      [self initNativeAppNavigationController];
 
     [[NSNotificationCenter defaultCenter]
         addObserver:self
            selector:@selector(applicationDidBecomeActive)
                name:UIApplicationDidBecomeActiveNotification
              object:nil];
   }
   return self;
 }
 
@@ skipping 1104 matching lines @@
   if (isPrerenderTab_ && !isLinkLoadingPrerenderTab_) {
     [delegate_ discardPrerender];
     return NO;
   }
   return YES;
 }
 
 - (BOOL)urlTriggersNativeAppLaunch:(const GURL&)url
                          sourceURL:(const GURL&)sourceURL
                        linkClicked:(BOOL)linkClicked {
+  // TODO(crbug/711511): If Native App Launcher is not enabled, returning NO
+  // bypasses all Link Navigation logic. This call should eventually be
+  // eliminated.
+  if (!experimental_flags::IsNativeAppLauncherEnabled())
+    return NO;
+
   // Don't open any native app directly when prerendering or from Incognito.
   if (isPrerenderTab_ || self.browserState->IsOffTheRecord())
     return NO;
 
   base::scoped_nsprotocol<id<NativeAppMetadata>> metadata(
       [[ios::GetChromeBrowserProvider()->GetNativeAppWhitelistManager()
           nativeAppForURL:url] retain]);
   if (![metadata shouldAutoOpenLinks])
     return NO;
 
@@ skipping 268 matching lines @@
             appendTo:kLastTab]);
     [self.view chromeExecuteCommand:command];
   } else {
     base::scoped_nsobject<GenericChromeCommand> chromeCommand(
         [[GenericChromeCommand alloc] initWithTag:IDC_NEW_INCOGNITO_TAB]);
     [self.view chromeExecuteCommand:chromeCommand];
   }
 }
 
 - (NativeAppNavigationController*)nativeAppNavigationController {
+  // TODO(crbug.com/711511): If Native App Launcher is not enabled, simply
+  // return nil here. This method should eventually be eliminated.
+  if (!experimental_flags::IsNativeAppLauncherEnabled())
+    return nil;
   return nativeAppNavigationController_;
 }
 
 - (void)initNativeAppNavigationController {
   if (browserState_->IsOffTheRecord())
     return;
   DCHECK(!nativeAppNavigationController_);
   nativeAppNavigationController_.reset(
       [[NativeAppNavigationController alloc] initWithWebState:self.webState]);
   DCHECK(nativeAppNavigationController_);
@@ skipping 40 matching lines @@
 
 - (TabModel*)parentTabModel {
   return parentTabModel_;
 }
 
 - (FormInputAccessoryViewController*)inputAccessoryViewController {
   return inputAccessoryViewController_.get();
 }
 
 @end