chrome/browser/ui/browser_navigator.cc

// Copyright 2012 The Chromium Authors
// 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_navigator.h"

#include <algorithm>
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <utility>

#include "base/memory/raw_ptr.h"
#include "base/notimplemented.h"
#include "base/notreached.h"
#include "base/strings/utf_string_conversions.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "chrome/browser/apps/app_service/web_contents_app_id_utils.h"
#include "chrome/browser/apps/link_capturing/link_capturing_tab_data.h"
#include "chrome/browser/browser_about_handler.h"
#include "chrome/browser/picture_in_picture/picture_in_picture_window_manager.h"
#include "chrome/browser/platform_util.h"
#include "chrome/browser/prefs/incognito_mode_prefs.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/renderer_host/chrome_navigation_ui_data.h"
#include "chrome/browser/signin/signin_promo.h"
#include "chrome/browser/tab_contents/tab_util.h"
#include "chrome/browser/ui/browser.h"
#include "chrome/browser/ui/browser_finder.h"
#include "chrome/browser/ui/browser_navigator_params.h"
#include "chrome/browser/ui/browser_window.h"
#include "chrome/browser/ui/location_bar/location_bar.h"
#include "chrome/browser/ui/singleton_tabs.h"
#include "chrome/browser/ui/status_bubble.h"
#include "chrome/browser/ui/tab_helpers.h"
#include "chrome/browser/ui/tabs/tab_strip_model.h"
#include "chrome/browser/ui/tabs/tab_strip_user_gesture_details.h"
#include "chrome/browser/ui/web_applications/app_browser_controller.h"
#include "chrome/browser/ui/web_applications/web_app_tabbed_utils.h"
#include "chrome/browser/web_applications/web_app_helpers.h"
#include "chrome/browser/web_applications/web_app_tab_helper.h"
#include "chrome/common/url_constants.h"
#include "components/captive_portal/core/buildflags.h"
#include "components/constrained_window/constrained_window_views.h"
#include "components/no_state_prefetch/browser/no_state_prefetch_manager.h"
#include "components/password_manager/content/common/web_ui_constants.h"
#include "components/policy/core/common/policy_pref_names.h"
#include "components/prefs/pref_service.h"
#include "content/public/browser/browser_url_handler.h"
#include "content/public/browser/navigation_entry.h"
#include "content/public/browser/picture_in_picture_window_controller.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/site_isolation_policy.h"
#include "content/public/browser/web_contents.h"
#include "extensions/buildflags/buildflags.h"
#include "ui/base/window_open_disposition.h"
#include "ui/display/display.h"
#include "ui/display/screen.h"
#include "url/url_constants.h"

#if !BUILDFLAG(IS_ANDROID)
#include "chrome/browser/ui/web_applications/navigation_capturing_process.h"
#include "chrome/browser/ui/web_applications/web_app_launch_utils.h"
#endif  // !BUILDFLAG(IS_ANDROID)

#if BUILDFLAG(IS_CHROMEOS)
#include "ash/public/cpp/multi_user_window_manager.h"
#include "chrome/browser/ui/ash/multi_user/multi_user_window_manager_helper.h"
#include "chrome/browser/ui/ash/system_web_apps/system_web_app_ui_utils.h"
#include "components/account_id/account_id.h"
#endif

#if defined(USE_AURA)
#include "ui/aura/window.h"
#endif

#if BUILDFLAG(ENABLE_CAPTIVE_PORTAL_DETECTION)
#include "components/captive_portal/content/captive_portal_tab_helper.h"
#endif

using content::GlobalRequestID;
using content::NavigationController;
using content::WebContents;
using WebExposedIsolationLevel = content::WebExposedIsolationLevel;

namespace {

// Returns true if |params.browser| exists and can open a new tab for
// |params.url|. Not all browsers support multiple tabs, such as app frames and
// popups. TYPE_APP will open a new tab if the browser was launched from a
// template, otherwise only if the URL is within the app scope.
bool WindowCanOpenTabs(const NavigateParams& params) {
  if (!params.browser) {
    return false;
  }

  // If the browser is created from a template, we do not need to check if the
  // url is in the app scope since we know it was saved directly from the app.
  if (params.browser->creation_source() !=
          Browser::CreationSource::kDeskTemplate &&
      params.browser->app_controller() &&
      !params.browser->app_controller()->IsUrlInAppScope(params.url)) {
    return false;
  }

  return params.browser->CanSupportWindowFeature(Browser::FEATURE_TABSTRIP) ||
         params.browser->tab_strip_model()->empty();
}

// Finds an existing Browser compatible with |profile|, making a new one if no
// such Browser is located.
Browser* GetOrCreateBrowser(Profile* profile, bool user_gesture) {
  Browser* browser = chrome::FindTabbedBrowser(profile, false);

  if (!browser && Browser::GetCreationStatusForProfile(profile) ==
                      Browser::CreationStatus::kOk) {
    browser = Browser::Create(Browser::CreateParams(profile, user_gesture));
  }
  return browser;
}

bool IncognitoModeForced(const Profile* profile) {
  return IncognitoModePrefs::GetAvailability(profile->GetPrefs()) ==
         policy::IncognitoModeAvailability::kForced;
}

// Change some of the navigation parameters based on the particular URL.
// Returns true on success. Otherwise, if changing params leads the browser
// into an erroneous state, returns false.
bool AdjustNavigateParamsForURL(NavigateParams* params) {
  // Check for some chrome:// pages which we always want to open in a
  // non-incognito window. Note that even though a ChromeOS guest session is
  // technically an incognito window, these URLs are allowed.
  Profile* profile = params->initiating_profile;
  if (!params->contents_to_insert && !params->switch_to_singleton_tab &&
      !IsURLAllowedInIncognito(params->url) && !profile->IsGuestSession() &&
      (profile->IsOffTheRecord() ||
       params->disposition == WindowOpenDisposition::OFF_THE_RECORD)) {
    profile = profile->GetOriginalProfile();

    // If incognito is forced, we punt.
    if (IncognitoModeForced(profile)) {
      return false;
    }
    params->disposition = WindowOpenDisposition::SINGLETON_TAB;
    params->browser = GetOrCreateBrowser(profile, params->user_gesture);
    params->window_action = NavigateParams::SHOW_WINDOW;
  }

  // Clicking a link to the home tab in a tabbed web app should always open the
  // link in the home tab.
  if (web_app::IsHomeTabUrl(params->browser, params->url)) {
    params->browser->tab_strip_model()->ActivateTabAt(0);
    // If the navigation URL is the same as the current home tab URL, skip the
    // navigation.
    if (params->browser->tab_strip_model()
            ->GetActiveWebContents()
            ->GetLastCommittedURL() == params->url) {
      return false;
    }
    params->disposition = WindowOpenDisposition::CURRENT_TAB;
  }

  return true;
}

Browser::ValueSpecified GetOriginSpecified(const NavigateParams& params) {
  return params.window_features.has_x && params.window_features.has_y
             ? Browser::ValueSpecified::kSpecified
             : Browser::ValueSpecified::kUnspecified;
}

// Returns a Browser and tab index. The browser can host the navigation or
// tab addition specified in |params|.  This might just return the same
// Browser specified in |params|, or some other if that Browser is deemed
// incompatible. The tab index will be -1 unless a singleton or tab switch
// was requested, in which case it might be the target tab index, or -1
// if not found.
std::tuple<Browser*, int> GetBrowserAndTabForDisposition(
    const NavigateParams& params) {
  Profile* profile = params.initiating_profile;

  switch (params.disposition) {
    case WindowOpenDisposition::SWITCH_TO_TAB:
#if !BUILDFLAG(IS_ANDROID)
    {
      std::pair<Browser*, int> browser_and_index =
          GetIndexAndBrowserOfExistingTab(profile, params);
      if (browser_and_index.first) {
        return browser_and_index;
      }
    }
#endif
      [[fallthrough]];
    case WindowOpenDisposition::CURRENT_TAB:
      if (params.browser) {
        return {params.browser, -1};
      }
      // Find a compatible window and re-execute this command in it. Otherwise
      // re-run with NEW_WINDOW.
      return {GetOrCreateBrowser(profile, params.user_gesture), -1};
    case WindowOpenDisposition::SINGLETON_TAB: {
      // If we have a browser window, check it first.
      if (params.browser) {
        int index = GetIndexOfExistingTab(params.browser, params);
        if (index >= 0) {
          return {params.browser, index};
        }
      }
      // If we don't have a a window, or if this window can't open tabs, then
      // it would load in a random window, potentially opening a second copy.
      // Instead, make an extra effort to see if there's an already open copy.
      if (!WindowCanOpenTabs(params)) {
        std::pair<Browser*, int> browser_and_index =
            GetIndexAndBrowserOfExistingTab(profile, params);
        if (browser_and_index.first) {
          return browser_and_index;
        }
      }
    }
      [[fallthrough]];
    case WindowOpenDisposition::NEW_FOREGROUND_TAB:
    case WindowOpenDisposition::NEW_BACKGROUND_TAB:
      // See if we can open the tab in the window this navigator is bound to.
      if (WindowCanOpenTabs(params)) {
        return {params.browser, -1};
      }

      // Find a compatible window and re-execute this command in it. Otherwise
      // re-run with NEW_WINDOW.
      return {GetOrCreateBrowser(profile, params.user_gesture), -1};
    case WindowOpenDisposition::NEW_PICTURE_IN_PICTURE:
#if !BUILDFLAG(IS_ANDROID)
    {
      // The picture in picture window should be part of the opener's web app,
      // if any.
      std::string app_name;
      if (!params.app_id.empty()) {
        app_name = web_app::GenerateApplicationNameFromAppId(params.app_id);
      } else if (params.browser && !params.browser->app_name().empty()) {
        app_name = params.browser->app_name();
      }

      auto browser_params = Browser::CreateParams::CreateForPictureInPicture(
          app_name, params.trusted_source, profile, params.user_gesture);
      DCHECK(params.contents_to_insert);
      auto pip_options =
          params.contents_to_insert->GetPictureInPictureOptions();
      if (!pip_options.has_value()) {
        return {nullptr, -1};
      }

      browser_params.pip_options = pip_options;

      const BrowserWindow* const browser_window = params.browser->window();
      const gfx::NativeWindow native_window =
          browser_window ? browser_window->GetNativeWindow()
                         : gfx::NativeWindow();
      const display::Screen* const screen = display::Screen::GetScreen();
      const display::Display display =
          browser_window ? screen->GetDisplayNearestWindow(native_window)
                         : screen->GetDisplayForNewWindows();

      browser_params.initial_bounds =
          PictureInPictureWindowManager::GetInstance()
              ->CalculateInitialPictureInPictureWindowBounds(*pip_options,
                                                             display);

      browser_params.omit_from_session_restore = true;
      return {Browser::Create(browser_params), -1};
    }
#else   // !IS_ANDROID
      // For TYPE_PICTURE_IN_PICTURE
      NOTIMPLEMENTED_LOG_ONCE();
      return {nullptr, -1};
#endif  // !IS_ANDROID

    case WindowOpenDisposition::NEW_POPUP: {
      // Make a new popup window.
      // Coerce app-style if |source| represents an app.
      std::string app_name;
      if (!params.app_id.empty()) {
        app_name = web_app::GenerateApplicationNameFromAppId(params.app_id);
      } else if (params.browser && !params.browser->app_name().empty()) {
        app_name = params.browser->app_name();
      }
      if (Browser::GetCreationStatusForProfile(profile) !=
          Browser::CreationStatus::kOk) {
        return {nullptr, -1};
      }
      if (app_name.empty()) {
        Browser::CreateParams browser_params(Browser::TYPE_POPUP, profile,
                                             params.user_gesture);
        browser_params.trusted_source = params.trusted_source;
        browser_params.initial_bounds = params.window_features.bounds;
        browser_params.initial_origin_specified = GetOriginSpecified(params);
        browser_params.can_maximize = !params.is_tab_modal_popup_deprecated;
        browser_params.can_fullscreen = !params.is_tab_modal_popup_deprecated;
        return {Browser::Create(browser_params), -1};
      }
      Browser::CreateParams browser_params =
          Browser::CreateParams::CreateForAppPopup(
              app_name, params.trusted_source, params.window_features.bounds,
              profile, params.user_gesture);
      browser_params.initial_origin_specified = GetOriginSpecified(params);
      return {Browser::Create(browser_params), -1};
    }
    case WindowOpenDisposition::NEW_WINDOW: {
      // Make a new normal browser window.
      Browser* browser = nullptr;
      if (Browser::GetCreationStatusForProfile(profile) ==
          Browser::CreationStatus::kOk) {
        browser = Browser::Create(
            Browser::CreateParams(profile, params.user_gesture));
      }
      return {browser, -1};
    }
    case WindowOpenDisposition::OFF_THE_RECORD:
      // Make or find an incognito window.
      return {GetOrCreateBrowser(
                  profile->GetPrimaryOTRProfile(/*create_if_needed=*/true),
                  params.user_gesture),
              -1};
    // The following types result in no navigation.
    case WindowOpenDisposition::SAVE_TO_DISK:
    case WindowOpenDisposition::IGNORE_ACTION:
      return {nullptr, -1};
    default:
      NOTREACHED();
  }
}

// Fix disposition and other parameter values depending on prevailing
// conditions.
void NormalizeDisposition(NavigateParams* params) {
  // Calculate the WindowOpenDisposition if necessary.
  if (params->browser->tab_strip_model()->empty() &&
      (params->disposition == WindowOpenDisposition::NEW_BACKGROUND_TAB ||
       params->disposition == WindowOpenDisposition::CURRENT_TAB ||
       params->disposition == WindowOpenDisposition::SINGLETON_TAB)) {
    params->disposition = WindowOpenDisposition::NEW_FOREGROUND_TAB;
  }
  if (params->browser->profile()->IsOffTheRecord() &&
      params->disposition == WindowOpenDisposition::OFF_THE_RECORD) {
    params->disposition = WindowOpenDisposition::NEW_FOREGROUND_TAB;
  }
  if (!params->source_contents &&
      params->disposition == WindowOpenDisposition::CURRENT_TAB) {
    params->disposition = WindowOpenDisposition::NEW_FOREGROUND_TAB;
  }

  switch (params->disposition) {
    case WindowOpenDisposition::NEW_BACKGROUND_TAB:
      // Disposition trumps add types. ADD_ACTIVE is a default, so we need to
      // remove it if disposition implies the tab is going to open in the
      // background.
      params->tabstrip_add_types &= ~AddTabTypes::ADD_ACTIVE;
      break;

    case WindowOpenDisposition::NEW_PICTURE_IN_PICTURE:
      PictureInPictureWindowManager::SetWindowParams(*params);
      break;

    case WindowOpenDisposition::NEW_WINDOW:
    case WindowOpenDisposition::NEW_POPUP: {
      // Code that wants to open a new window typically expects it to be shown
      // automatically.
      if (params->window_action == NavigateParams::NO_ACTION) {
        params->window_action = NavigateParams::SHOW_WINDOW;
      }
      [[fallthrough]];
    }
    case WindowOpenDisposition::NEW_FOREGROUND_TAB:
    case WindowOpenDisposition::SINGLETON_TAB:
      params->tabstrip_add_types |= AddTabTypes::ADD_ACTIVE;
      break;

    default:
      break;
  }
}

// Obtain the profile used by the code that originated the Navigate() request.
Profile* GetSourceProfile(NavigateParams* params) {
  // |source_site_instance| needs to be checked before |source_contents|. This
  // might matter when chrome.windows.create is used to open multiple URLs,
  // which would reuse |params| and modify |params->source_contents| across
  // navigations.
  if (params->source_site_instance) {
    return Profile::FromBrowserContext(
        params->source_site_instance->GetBrowserContext());
  }

  if (params->source_contents) {
    return Profile::FromBrowserContext(
        params->source_contents->GetBrowserContext());
  }

  return params->initiating_profile;
}

base::WeakPtr<content::NavigationHandle> LoadURLInContents(
    WebContents* target_contents,
    const GURL& url,
    NavigateParams* params) {
  NavigationController::LoadURLParams load_url_params(url);
  load_url_params.initiator_frame_token = params->initiator_frame_token;
  load_url_params.initiator_process_id = params->initiator_process_id;
  load_url_params.initiator_origin = params->initiator_origin;
  load_url_params.initiator_base_url = params->initiator_base_url;
  load_url_params.source_site_instance = params->source_site_instance;
  load_url_params.referrer = params->referrer;
  load_url_params.frame_name = params->frame_name;
  load_url_params.frame_tree_node_id = params->frame_tree_node_id;
  load_url_params.redirect_chain = params->redirect_chain;
  load_url_params.transition_type = params->transition;
  load_url_params.extra_headers = params->extra_headers;
  load_url_params.should_replace_current_entry =
      params->should_replace_current_entry;
  load_url_params.is_renderer_initiated = params->is_renderer_initiated;
  load_url_params.started_from_context_menu = params->started_from_context_menu;
  load_url_params.has_user_gesture = params->user_gesture;
  load_url_params.blob_url_loader_factory = params->blob_url_loader_factory;
  load_url_params.input_start = params->input_start;
  load_url_params.was_activated = params->was_activated;
  load_url_params.href_translate = params->href_translate;
  load_url_params.reload_type = params->reload_type;
  load_url_params.impression = params->impression;
  load_url_params.suggested_system_entropy = params->suggested_system_entropy;

  // |frame_tree_node_id| is invalid for main frame navigations.
  if (params->frame_tree_node_id.is_null()) {
    bool force_no_https_upgrade =
        params->url_typed_with_http_scheme ||
        params->captive_portal_window_type !=
            captive_portal::CaptivePortalWindowType::kNone;
    std::unique_ptr<ChromeNavigationUIData> navigation_ui_data =
        ChromeNavigationUIData::CreateForMainFrameNavigation(
            target_contents, params->is_using_https_as_default_scheme,
            force_no_https_upgrade);
    navigation_ui_data->set_navigation_initiated_from_sync(
        params->navigation_initiated_from_sync);
    load_url_params.navigation_ui_data = std::move(navigation_ui_data);
  }

  if (params->post_data) {
    load_url_params.load_type = NavigationController::LOAD_TYPE_HTTP_POST;
    load_url_params.post_data = params->post_data;
  }

  return target_contents->GetController().LoadURLWithParams(load_url_params);
}

// This class makes sure the Browser object held in |params| is made visible
// by the time it goes out of scope, provided |params| wants it to be shown.
class ScopedBrowserShower {
 public:
  explicit ScopedBrowserShower(NavigateParams* params,
                               content::WebContents** contents)
      : params_(params), contents_(contents) {}

  ScopedBrowserShower(const ScopedBrowserShower&) = delete;
  ScopedBrowserShower& operator=(const ScopedBrowserShower&) = delete;

  ~ScopedBrowserShower() {
    BrowserWindow* window = params_->browser->window();
    if (params_->window_action == NavigateParams::SHOW_WINDOW_INACTIVE) {
      // TODO(crbug.com/40284685): investigate if SHOW_WINDOW_INACTIVE needs to
      // be supported for tab modal popups.
      CHECK_EQ(params_->is_tab_modal_popup_deprecated, false);
      window->ShowInactive();
    } else if (params_->window_action == NavigateParams::SHOW_WINDOW) {
      if (params_->is_tab_modal_popup_deprecated) {
        CHECK_EQ(params_->disposition, WindowOpenDisposition::NEW_POPUP);
        CHECK_NE(source_contents_, nullptr);
        window->SetIsTabModalPopupDeprecated(true);
        constrained_window::ShowModalDialog(window->GetNativeWindow(),
                                            source_contents_);
      } else {
        window->Show();
      }
      // If a user gesture opened a popup window, focus the contents.
      if (params_->user_gesture &&
          (params_->disposition == WindowOpenDisposition::NEW_POPUP ||
           params_->disposition ==
               WindowOpenDisposition::NEW_PICTURE_IN_PICTURE) &&
          *contents_) {
        (*contents_)->Focus();
        window->Activate();
      }
    }
  }

  void set_source_contents(content::WebContents* source_contents) {
    source_contents_ = source_contents;
  }

 private:
  raw_ptr<NavigateParams> params_;
  raw_ptr<content::WebContents*> contents_;
  raw_ptr<content::WebContents> source_contents_;
};

std::unique_ptr<content::WebContents> CreateTargetContents(
    const NavigateParams& params,
    const GURL& url) {
  // Always create the new WebContents in a new SiteInstance (and therefore a
  // new BrowsingInstance), *unless* there's a |params.opener|.
  //
  // Note that the SiteInstance below is only for the "initial" placement of the
  // new WebContents (i.e. if subsequent navigation [including the initial
  // navigation] triggers a cross-process transfer, then the opener and new
  // contents can end up in separate processes).  This is fine, because even if
  // subsequent navigation is cross-process (i.e. cross-SiteInstance), then it
  // will stay in the same BrowsingInstance (creating frame proxies as needed)
  // preserving the requested opener relationship along the way.
  scoped_refptr<content::SiteInstance> initial_site_instance_for_new_contents =
      params.opener
          ? params.opener->GetSiteInstance()
          : tab_util::GetSiteInstanceForNewTab(params.browser->profile(), url);

  WebContents::CreateParams create_params(
      params.browser->profile(), initial_site_instance_for_new_contents);
  create_params.main_frame_name = params.frame_name;
  if (params.opener) {
    create_params.opener_render_frame_id = params.opener->GetRoutingID();
    create_params.opener_render_process_id =
        params.opener->GetProcess()->GetDeprecatedID();
  }

  create_params.opened_by_another_window = params.opened_by_another_window;

  if (params.disposition == WindowOpenDisposition::NEW_BACKGROUND_TAB) {
    create_params.initially_hidden = true;
  }

#if defined(USE_AURA)
  if (params.browser->window() && params.browser->window()->GetNativeWindow()) {
    create_params.context = params.browser->window()->GetNativeWindow();
  }
#endif

  return WebContents::Create(create_params);
}

bool IsHostAllowedInIncognito(const GURL& url) {
  std::string scheme = url.scheme();
  std::string_view host = url.host_piece();
  if (scheme != content::kChromeUIScheme) {
    return true;
  }

  if (host == chrome::kChromeUIChromeSigninHost) {
#if BUILDFLAG(IS_WIN)
    // Allow incognito mode for the chrome-signin url if we only want to
    // retrieve the login scope token without touching any profiles. This
    // option is only available on Windows for use with Google Credential
    // Provider for Windows.
    return signin::GetSigninReasonForEmbeddedPromoURL(url) ==
           signin_metrics::Reason::kFetchLstOnly;
#else
    return false;
#endif  // BUILDFLAG(IS_WIN)
  }

  // Most URLs are allowed in incognito; the following are exceptions.
  // chrome://extensions is on the list because it redirects to
  // chrome://settings.
  return host != chrome::kChromeUIAppLauncherPageHost &&
         host != chrome::kChromeUISettingsHost &&
#if BUILDFLAG(IS_CHROMEOS)
         host != chrome::kChromeUIOSSettingsHost &&
#endif
         host != chrome::kChromeUIHelpHost &&
         host != chrome::kChromeUIHistoryHost &&
         host != chrome::kChromeUIExtensionsHost &&
         host != password_manager::kChromeUIPasswordManagerHost;
}

}  // namespace

base::WeakPtr<content::NavigationHandle> Navigate(NavigateParams* params) {
  TRACE_EVENT1("navigation", "chrome::Navigate", "disposition",
               params->disposition);
  Browser* source_browser = params->browser;
  if (source_browser) {
    params->initiating_profile = source_browser->profile();
  }
  DCHECK(params->initiating_profile);

  // If the created window is a partitioned popin, a valid source exists, and
  // the disposition is NEW_POPUP then the resulting popup should be tab-modal.
  // See: https://explainers-by-googlers.github.io/partitioned-popins/
  params->is_tab_modal_popup_deprecated |=
      params->window_features.is_partitioned_popin && params->source_contents &&
      params->disposition == WindowOpenDisposition::NEW_POPUP;

#if BUILDFLAG(IS_CHROMEOS)
  if (params->initiating_profile->IsOffTheRecord() &&
      params->initiating_profile->GetOTRProfileID().IsCaptivePortal() &&
      params->disposition != WindowOpenDisposition::NEW_POPUP &&
      params->disposition != WindowOpenDisposition::CURRENT_TAB &&
      !IncognitoModeForced(params->initiating_profile)) {
    // Navigation outside of the current tab or the initial popup window from a
    // captive portal signin window should be prevented.
    params->disposition = WindowOpenDisposition::CURRENT_TAB;
  }
#endif

  if (params->initiating_profile->ShutdownStarted()) {
    // Don't navigate when the profile is shutting down.
    return nullptr;
  }

  if (params->browser && params->browser->IsBrowserClosing()) {
    return nullptr;
  }

  // Block navigation requests when in locked fullscreen mode. We allow
  // navigation requests in the webapp when locked for OnTask (only relevant for
  // non-web browser scenarios).
  // TODO(b/365146870): Remove once we consolidate locked fullscreen with
  // OnTask.
  if (source_browser) {
    bool should_block_navigation =
        platform_util::IsBrowserLockedFullscreen(source_browser);
#if BUILDFLAG(IS_CHROMEOS)
    if (source_browser->IsLockedForOnTask()) {
      should_block_navigation = false;
    }
#endif  // BUILDFLAG(IS_CHROMEOS)
    if (should_block_navigation) {
      return nullptr;
    }
  }

  // Open System Apps in their standalone window if necessary.
  // TODO(crbug.com/40136163): Remove this code after we integrate with intent
  // handling.
#if BUILDFLAG(IS_CHROMEOS)
  const std::optional<ash::SystemWebAppType> capturing_system_app_type =
      ash::GetCapturingSystemAppForURL(params->initiating_profile, params->url);
  if (capturing_system_app_type &&
      (!params->browser ||
       !ash::IsBrowserForSystemWebApp(params->browser,
                                      capturing_system_app_type.value()))) {
    ash::SystemAppLaunchParams swa_params;
    swa_params.url = params->url;
    ash::LaunchSystemWebAppAsync(params->initiating_profile,
                                 capturing_system_app_type.value(), swa_params);

    // It's okay to early return here, because LaunchSystemWebAppAsync uses a
    // different logic to choose (and create if necessary) a browser window for
    // system apps.
    //
    // It's okay to skip the checks and cleanups below. The link captured system
    // app will either open in its own browser window, or navigate an existing
    // browser window exclusively used by this app. For the initiating browser,
    // the navigation should appear to be cancelled.
    return nullptr;
  }
#endif

  if (!AdjustNavigateParamsForURL(params)) {
    return nullptr;
  }

  // Picture-in-picture browser windows must have a source contents in order for
  // the window to function correctly. If we have no source contents to work
  // with (e.g. if an extension popup attempts to open a PiP window), we should
  // cancel the navigation.  The source URL must also be of a type that's
  // allowed to open document PiP.  See `PictureInPictureWindowManager` for
  // details on what's allowed.
  if (params->disposition == WindowOpenDisposition::NEW_PICTURE_IN_PICTURE) {
    const GURL& url = params->source_contents
                          ? params->source_contents->GetLastCommittedURL()
                          : GURL();
    if (!PictureInPictureWindowManager::IsSupportedForDocumentPictureInPicture(
            url)) {
      return nullptr;
    }
  }

  // If no source WebContents was specified, we use the selected one from the
  // target browser. This must happen before GetBrowserAndTabForDisposition()
  // has a chance to replace |params->browser| with another one, but after the
  // above check that relies on the original source_contents value.
  if (!params->source_contents && params->browser) {
    params->source_contents =
        params->browser->tab_strip_model()->GetActiveWebContents();
  }

  WebContents* contents_to_navigate_or_insert =
      params->contents_to_insert.get();
  if (params->switch_to_singleton_tab) {
    DCHECK_EQ(params->disposition, WindowOpenDisposition::SINGLETON_TAB);
    contents_to_navigate_or_insert = params->switch_to_singleton_tab;
  }

#if !BUILDFLAG(IS_ANDROID)
  // If this is a Picture in Picture window, then notify the pip manager about
  // it. This enables the opener and pip window to stay connected, so that (for
  // example), the pip window does not outlive the opener.
  //
  // We do this before creating the browser window, so that the browser can talk
  // to the PictureInPictureWindowManager.  Otherwise, the manager has no idea
  // that there's a pip window.
  if (params->disposition == WindowOpenDisposition::NEW_PICTURE_IN_PICTURE) {
    // Picture in picture windows may not be opened by other picture in
    // picture windows, or without an opener.
    if (!params->browser || params->browser->is_type_picture_in_picture()) {
      params->browser = nullptr;
      return nullptr;
    }

    PictureInPictureWindowManager::GetInstance()->EnterDocumentPictureInPicture(
        params->source_contents, contents_to_navigate_or_insert);
  }
#endif  // !BUILDFLAG(IS_ANDROID)

  // TODO(crbug.com/364657540): Revisit integration with web_application system
  // later if needed.
  int singleton_index;

#if !BUILDFLAG(IS_ANDROID)
  std::unique_ptr<web_app::NavigationCapturingProcess> app_navigation =
      web_app::NavigationCapturingProcess::MaybeHandleAppNavigation(*params);
  std::optional<std::tuple<Browser*, int>> app_browser_tab_override;
  if (app_navigation) {
    app_browser_tab_override =
        app_navigation->GetInitialBrowserAndTabOverrideForNavigation(*params);
  }
  std::tie(params->browser, singleton_index) =
      app_browser_tab_override.has_value()
          ? *app_browser_tab_override
          : GetBrowserAndTabForDisposition(*params);
#else  // !BUILDFLAG(IS_ANDROID)
  std::tie(params->browser, singleton_index) =
      GetBrowserAndTabForDisposition(*params);
#endif

  if (!params->browser) {
    return nullptr;
  }

  // Trying to open a background tab when in a non-tabbed app browser results in
  // focusing a regular browser window and opening a tab in the background
  // of that window. Change the disposition to NEW_FOREGROUND_TAB so that
  // the new tab is focused.
  if (source_browser && source_browser->is_type_app() &&
      params->disposition == WindowOpenDisposition::NEW_BACKGROUND_TAB &&
      !(source_browser->app_controller() &&
        source_browser->app_controller()->has_tab_strip())) {
    params->disposition = WindowOpenDisposition::NEW_FOREGROUND_TAB;
  }

  if (singleton_index != -1) {
    contents_to_navigate_or_insert =
        params->browser->tab_strip_model()->GetWebContentsAt(singleton_index);
  } else if (params->disposition == WindowOpenDisposition::SWITCH_TO_TAB) {
    // The user is trying to open a tab that no longer exists. If we open a new
    // tab, it could leave orphaned NTPs around, but always overwriting the
    // current tab could could clobber state that the user was trying to
    // preserve. Fallback to the behavior used for singletons: overwrite the
    // current tab if it's the NTP, otherwise open a new tab.
    params->disposition = WindowOpenDisposition::SINGLETON_TAB;
    ShowSingletonTabOverwritingNTP(params);
    return nullptr;
  }
  if (content::SiteIsolationPolicy::ShouldUrlUseApplicationIsolationLevel(
          params->initiating_profile, params->url)) {
    CHECK(web_app::AppBrowserController::IsWebApp(params->browser));
  }
#if BUILDFLAG(IS_CHROMEOS)
  if (source_browser && source_browser != params->browser) {
    // When the newly created browser was spawned by a browser which visits
    // another user's desktop, it should be shown on the same desktop as the
    // originating one. (This is part of the desktop separation per profile).
    auto* window_manager = MultiUserWindowManagerHelper::GetWindowManager();
    // Some unit tests have no client instantiated.
    if (window_manager) {
      aura::Window* src_window = source_browser->window()->GetNativeWindow();
      aura::Window* new_window = params->browser->window()->GetNativeWindow();
      const AccountId& src_account_id =
          window_manager->GetUserPresentingWindow(src_window);
      if (src_account_id !=
          window_manager->GetUserPresentingWindow(new_window)) {
        // Once the window gets presented, it should be shown on the same
        // desktop as the desktop of the creating browser. Note that this
        // command will not show the window if it wasn't shown yet by the
        // browser creation.
        window_manager->ShowWindowForUser(new_window, src_account_id);
      }
    }
  }
#endif

  // Navigate() must not return early after this point.

  if (GetSourceProfile(params) != params->browser->profile()) {
    // A tab is being opened from a link from a different profile, we must reset
    // source information that may cause state to be shared.
    params->opener = nullptr;
    params->source_contents = nullptr;
    params->source_site_instance = nullptr;
    params->referrer = content::Referrer();
  }

  // Make sure the Browser is shown if params call for it.
  ScopedBrowserShower shower(params, &contents_to_navigate_or_insert);
  if (params->is_tab_modal_popup_deprecated) {
    shower.set_source_contents(params->source_contents);
  }

  // Some dispositions need coercion to base types.
  NormalizeDisposition(params);

  // If a new window has been created, it needs to be shown.
  if (params->window_action == NavigateParams::NO_ACTION &&
      source_browser != params->browser &&
      params->browser->tab_strip_model()->empty()) {
    params->window_action = NavigateParams::SHOW_WINDOW;
  }

  // If we create a popup window from a non user-gesture, don't activate it.
  if (params->window_action == NavigateParams::SHOW_WINDOW &&
      params->disposition == WindowOpenDisposition::NEW_POPUP &&
      params->user_gesture == false) {
    params->window_action = NavigateParams::SHOW_WINDOW_INACTIVE;
  }

  // Determine if the navigation was user initiated. If it was, we need to
  // inform the target WebContents, and we may need to update the UI.
  bool user_initiated =
      params->transition & ui::PAGE_TRANSITION_FROM_ADDRESS_BAR ||
      !ui::PageTransitionIsWebTriggerable(params->transition);

  base::WeakPtr<content::NavigationHandle> navigation_handle;

  std::unique_ptr<tabs::TabModel> tab_to_insert;
  if (params->contents_to_insert) {
    tab_to_insert =
        std::make_unique<tabs::TabModel>(std::move(params->contents_to_insert),
                                         params->browser->tab_strip_model());
  }

  // If no target WebContents was specified (and we didn't seek and find a
  // singleton), we need to construct one if we are supposed to target a new
  // tab.
  if (!contents_to_navigate_or_insert) {
    DCHECK(!params->url.is_empty());
    if (params->disposition != WindowOpenDisposition::CURRENT_TAB) {
      tab_to_insert = std::make_unique<tabs::TabModel>(
          CreateTargetContents(*params, params->url),
          params->browser->tab_strip_model());
      contents_to_navigate_or_insert = tab_to_insert->GetContents();

      apps::SetAppIdForWebContents(params->browser->profile(),
                                   contents_to_navigate_or_insert,
                                   params->app_id);
#if BUILDFLAG(ENABLE_CAPTIVE_PORTAL_DETECTION)
      captive_portal::CaptivePortalTabHelper::FromWebContents(
          contents_to_navigate_or_insert)
          ->set_window_type(params->captive_portal_window_type);
#endif
    } else {
      // ... otherwise if we're loading in the current tab, the target is the
      // same as the source.
      DCHECK(params->source_contents);
      contents_to_navigate_or_insert = params->source_contents;
    }

    // Try to handle non-navigational URLs that popup dialogs and such, these
    // should not actually navigate.
    if (!HandleNonNavigationAboutURL(
            params->url, contents_to_navigate_or_insert->GetBrowserContext())) {
      // Perform the actual navigation, tracking whether it came from the
      // renderer.
      navigation_handle = LoadURLInContents(contents_to_navigate_or_insert,
                                            params->url, params);
    }
  } else {
    // |contents_to_navigate_or_insert| was specified non-NULL, and so we assume
    // it has already been navigated appropriately. We need to do nothing more
    // other than add it to the appropriate tabstrip.
  }

  // If the user navigated from the omnibox, and the selected tab is going to
  // lose focus, then make sure the focus for the source tab goes away from the
  // omnibox.
  if (params->source_contents &&
      (params->disposition == WindowOpenDisposition::NEW_FOREGROUND_TAB ||
       params->disposition == WindowOpenDisposition::NEW_WINDOW) &&
      (params->tabstrip_add_types & AddTabTypes::ADD_INHERIT_OPENER)) {
    params->source_contents->Focus();
  }

  if (tab_to_insert) {
    // Save data needed for link capturing into apps that cannot otherwise be
    // inferred later in the navigation. These are only needed when the
    // navigation happens in a different tab to the link click.
    apps::SetLinkCapturingSourceDisposition(tab_to_insert->GetContents(),
                                            params->disposition);
  }

  if (params->source_contents == contents_to_navigate_or_insert) {
    // The navigation occurred in the source tab.
    params->browser->UpdateUIForNavigationInTab(
        contents_to_navigate_or_insert, params->transition,
        params->window_action, user_initiated);
  } else if (singleton_index == -1) {
    if (source_browser != params->browser) {
      params->tabstrip_index = params->browser->tab_strip_model()->count();
    }

    // If some non-default value is set for the index, we should tell the
    // TabStripModel to respect it.
    if (params->tabstrip_index != -1) {
      params->tabstrip_add_types |= AddTabTypes::ADD_FORCE_INDEX;
    }

    // Maybe notify that an open operation has been done from a gesture.
    // TODO(crbug.com/40719979): preferably pipe this information through the
    // TabStripModel instead. See bug for deeper discussion.
    if (params->user_gesture && source_browser == params->browser) {
      params->browser->window()->LinkOpeningFromGesture(params->disposition);
    }

    DCHECK(tab_to_insert);
    // The navigation should insert a new tab into the target Browser.
    params->browser->tab_strip_model()->AddTab(
        std::move(tab_to_insert), params->tabstrip_index, params->transition,
        params->tabstrip_add_types, params->group);
  }

  if (singleton_index >= 0) {
    // If switching browsers, make sure it is shown.
    if (params->disposition == WindowOpenDisposition::SWITCH_TO_TAB &&
        params->browser != source_browser) {
      params->window_action = NavigateParams::SHOW_WINDOW;
    }

    if (contents_to_navigate_or_insert->IsCrashed()) {
      contents_to_navigate_or_insert->GetController().Reload(
          content::ReloadType::NORMAL, true);
    } else if (params->path_behavior == NavigateParams::IGNORE_AND_NAVIGATE &&
               contents_to_navigate_or_insert->GetURL() != params->url) {
      navigation_handle = LoadURLInContents(contents_to_navigate_or_insert,
                                            params->url, params);
    }

    // If the singleton tab isn't already selected, select it.
    if (params->source_contents != contents_to_navigate_or_insert) {
      // Use the index before the potential close below, because it could
      // make the index refer to a different tab.
      auto gesture_type = user_initiated
                              ? TabStripUserGestureDetails::GestureType::kOther
                              : TabStripUserGestureDetails::GestureType::kNone;
      bool should_close_this_tab = false;
      if (params->disposition == WindowOpenDisposition::SWITCH_TO_TAB) {
        // Close orphaned NTP (and the like) with no history when the user
        // switches away from them.
        if (params->source_contents) {
          if (params->source_contents->GetController().CanGoBack() ||
              (params->source_contents->GetLastCommittedURL().spec() !=
                   chrome::kChromeUINewTabURL &&
               params->source_contents->GetLastCommittedURL().spec() !=
                   url::kAboutBlankURL)) {
            // Blur location bar before state save in ActivateTabAt() below.
            params->source_contents->Focus();
          } else {
            should_close_this_tab = true;
          }
        }
      }
      params->browser->tab_strip_model()->ActivateTabAt(
          singleton_index, TabStripUserGestureDetails(gesture_type));
      // Close tab after switch so index remains correct.
      if (should_close_this_tab) {
        params->source_contents->Close();
      }
    }
  }

  params->navigated_or_inserted_contents = contents_to_navigate_or_insert;

// At this point, the `params->navigated_or_inserted_contents` is guaranteed to
// be non null, so perform tasks if the navigation has been captured by a web
// app, like enqueueing launch params.
#if !BUILDFLAG(IS_ANDROID)
  if (app_navigation) {
    web_app::NavigationCapturingProcess::AfterWebContentsCreation(
        std::move(app_navigation), *params->navigated_or_inserted_contents,
        navigation_handle.get());
  }
#endif  // !BUILDFLAG(IS_ANDROID)
  return navigation_handle;
}

bool IsURLAllowedInIncognito(const GURL& url) {
  if (url.scheme() == content::kViewSourceScheme) {
    // A view-source URL is allowed in incognito mode only if the URL itself
    // is allowed in incognito mode. Remove the "view-source:" from the start
    // of the URL and validate the rest.
    const size_t scheme_len = strlen(content::kViewSourceScheme);
    CHECK_GT(url.spec().size(), scheme_len);
    std::string_view stripped_url_str(url.spec());
    // Adding +1 for ':' character.
    stripped_url_str.remove_prefix(scheme_len + 1);
    const GURL stripped_url(stripped_url_str);
    if (stripped_url.is_empty()) {
      return true;
    }
    return stripped_url.is_valid() && IsURLAllowedInIncognito(stripped_url);
  }

  return IsHostAllowedInIncognito(url);
}