chrome/browser/ui/browser_navigator.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/ui/browser_navigator.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/command_line.h"
  10 #include "base/prefs/pref_service.h"
  11 #include "base/strings/stringprintf.h"
  12 #include "base/strings/utf_string_conversions.h"
  13 #include "chrome/browser/browser_about_handler.h"
  14 #include "chrome/browser/chrome_notification_types.h"
  15 #include "chrome/browser/extensions/extension_service.h"
  16 #include "chrome/browser/extensions/tab_helper.h"
  17 #include "chrome/browser/google/google_url_tracker.h"
  18 #include "chrome/browser/prefs/incognito_mode_prefs.h"
  19 #include "chrome/browser/prerender/prerender_manager.h"
  20 #include "chrome/browser/prerender/prerender_manager_factory.h"
  21 #include "chrome/browser/prerender/prerender_util.h"
  22 #include "chrome/browser/profiles/profile.h"
  23 #include "chrome/browser/tab_contents/tab_util.h"
  24 #include "chrome/browser/ui/browser.h"
  25 #include "chrome/browser/ui/browser_finder.h"
  26 #include "chrome/browser/ui/browser_instant_controller.h"
  27 #include "chrome/browser/ui/browser_tab_contents.h"
  28 #include "chrome/browser/ui/browser_window.h"
  29 #include "chrome/browser/ui/host_desktop.h"
  30 #include "chrome/browser/ui/omnibox/location_bar.h"
  31 #include "chrome/browser/ui/search/instant_search_prerenderer.h"
  32 #include "chrome/browser/ui/singleton_tabs.h"
  33 #include "chrome/browser/ui/status_bubble.h"
  34 #include "chrome/browser/ui/tabs/tab_strip_model.h"
  35 #include "chrome/browser/web_applications/web_app.h"
  36 #include "chrome/common/pref_names.h"
  37 #include "chrome/common/url_constants.h"
  38 #include "content/public/browser/browser_url_handler.h"
  39 #include "content/public/browser/navigation_entry.h"
  40 #include "content/public/browser/notification_service.h"
  41 #include "content/public/browser/render_view_host.h"
  42 #include "content/public/browser/web_contents.h"
  43 #include "content/public/browser/web_contents_view.h"
  44 #include "extensions/common/extension.h"
  45
  46 #if defined(USE_ASH)
  47 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
  48 #endif
  49 #if defined(USE_AURA)
  50 #include "ui/aura/window.h"
  51 #endif
  52
  53 using content::GlobalRequestID;
  54 using content::NavigationController;
  55 using content::WebContents;
  56
  57 class BrowserNavigatorWebContentsAdoption {
  58  public:
  59   static void AttachTabHelpers(content::WebContents* contents) {
  60     BrowserTabContents::AttachTabHelpers(contents);
  61   }
  62 };
  63
  64 namespace {
  65
  66 // Returns true if the specified Browser can open tabs. Not all Browsers support
  67 // multiple tabs, such as app frames and popups. This function returns false for
  68 // those types of Browser.
  69 bool WindowCanOpenTabs(Browser* browser) {
  70   return browser->CanSupportWindowFeature(Browser::FEATURE_TABSTRIP) ||
  71       browser->tab_strip_model()->empty();
  72 }
  73
  74 // Finds an existing Browser compatible with |profile|, making a new one if no
  75 // such Browser is located.
  76 Browser* GetOrCreateBrowser(Profile* profile,
  77                             chrome::HostDesktopType host_desktop_type) {
  78   Browser* browser = chrome::FindTabbedBrowser(profile, false,
  79                                                host_desktop_type);
  80   return browser ? browser : new Browser(
  81       Browser::CreateParams(profile, host_desktop_type));
  82 }
  83
  84 // Change some of the navigation parameters based on the particular URL.
  85 // Currently this applies to some chrome:// pages which we always want to open
  86 // in a non-incognito window. Note that even though a ChromeOS guest session is
  87 // technically an incognito window, these URLs are allowed.
  88 // Returns true on success. Otherwise, if changing params leads the browser into
  89 // an erroneous state, returns false.
  90 bool AdjustNavigateParamsForURL(chrome::NavigateParams* params) {
  91   if (params->target_contents != NULL ||
  92       chrome::IsURLAllowedInIncognito(params->url,
  93                                       params->initiating_profile) ||
  94       params->initiating_profile->IsGuestSession()) {
  95     return true;
  96   }
  97
  98   Profile* profile = params->initiating_profile;
  99
 100   if (profile->IsOffTheRecord() || params->disposition == OFF_THE_RECORD) {
 101     profile = profile->GetOriginalProfile();
 102
 103     // If incognito is forced, we punt.
 104     PrefService* prefs = profile->GetPrefs();
 105     if (prefs && IncognitoModePrefs::GetAvailability(prefs) ==
 106             IncognitoModePrefs::FORCED) {
 107       return false;
 108     }
 109
 110     params->disposition = SINGLETON_TAB;
 111     params->browser = GetOrCreateBrowser(profile, params->host_desktop_type);
 112     params->window_action = chrome::NavigateParams::SHOW_WINDOW;
 113   }
 114
 115   return true;
 116 }
 117
 118 // Returns a Browser that can host the navigation or tab addition specified in
 119 // |params|. This might just return the same Browser specified in |params|, or
 120 // some other if that Browser is deemed incompatible.
 121 Browser* GetBrowserForDisposition(chrome::NavigateParams* params) {
 122   // If no source WebContents was specified, we use the selected one from
 123   // the target browser. This must happen first, before
 124   // GetBrowserForDisposition() has a chance to replace |params->browser| with
 125   // another one.
 126   if (!params->source_contents && params->browser) {
 127     params->source_contents =
 128         params->browser->tab_strip_model()->GetActiveWebContents();
 129   }
 130
 131   Profile* profile = params->initiating_profile;
 132
 133   switch (params->disposition) {
 134     case CURRENT_TAB:
 135       if (params->browser)
 136         return params->browser;
 137       // Find a compatible window and re-execute this command in it. Otherwise
 138       // re-run with NEW_WINDOW.
 139       return GetOrCreateBrowser(profile, params->host_desktop_type);
 140     case SINGLETON_TAB:
 141     case NEW_FOREGROUND_TAB:
 142     case NEW_BACKGROUND_TAB:
 143       // See if we can open the tab in the window this navigator is bound to.
 144       if (params->browser && WindowCanOpenTabs(params->browser))
 145         return params->browser;
 146       // Find a compatible window and re-execute this command in it. Otherwise
 147       // re-run with NEW_WINDOW.
 148       return GetOrCreateBrowser(profile, params->host_desktop_type);
 149     case NEW_POPUP: {
 150       // Make a new popup window.
 151       // Coerce app-style if |source| represents an app.
 152       std::string app_name;
 153       if (!params->extension_app_id.empty()) {
 154         app_name = web_app::GenerateApplicationNameFromExtensionId(
 155             params->extension_app_id);
 156       } else if (params->browser && !params->browser->app_name().empty()) {
 157         app_name = params->browser->app_name();
 158       } else if (params->source_contents) {
 159         extensions::TabHelper* extensions_tab_helper =
 160             extensions::TabHelper::FromWebContents(params->source_contents);
 161         if (extensions_tab_helper && extensions_tab_helper->is_app()) {
 162           app_name = web_app::GenerateApplicationNameFromExtensionId(
 163               extensions_tab_helper->extension_app()->id());
 164         }
 165       }
 166       if (app_name.empty()) {
 167         Browser::CreateParams browser_params(
 168             Browser::TYPE_POPUP, profile, params->host_desktop_type);
 169         browser_params.initial_bounds = params->window_bounds;
 170         return new Browser(browser_params);
 171       }
 172
 173       return new Browser(Browser::CreateParams::CreateForApp(
 174           Browser::TYPE_POPUP, app_name, params->window_bounds, profile,
 175           params->host_desktop_type));
 176     }
 177     case NEW_WINDOW: {
 178       // Make a new normal browser window.
 179       return new Browser(Browser::CreateParams(profile,
 180                                                params->host_desktop_type));
 181     }
 182     case OFF_THE_RECORD:
 183       // Make or find an incognito window.
 184       return GetOrCreateBrowser(profile->GetOffTheRecordProfile(),
 185                                 params->host_desktop_type);
 186     // The following types all result in no navigation.
 187     case SUPPRESS_OPEN:
 188     case SAVE_TO_DISK:
 189     case IGNORE_ACTION:
 190       return NULL;
 191     default:
 192       NOTREACHED();
 193   }
 194   return NULL;
 195 }
 196
 197 // Fix disposition and other parameter values depending on prevailing
 198 // conditions.
 199 void NormalizeDisposition(chrome::NavigateParams* params) {
 200   // Calculate the WindowOpenDisposition if necessary.
 201   if (params->browser->tab_strip_model()->empty() &&
 202       (params->disposition == NEW_BACKGROUND_TAB ||
 203        params->disposition == CURRENT_TAB ||
 204        params->disposition == SINGLETON_TAB)) {
 205     params->disposition = NEW_FOREGROUND_TAB;
 206   }
 207   if (params->browser->profile()->IsOffTheRecord() &&
 208       params->disposition == OFF_THE_RECORD) {
 209     params->disposition = NEW_FOREGROUND_TAB;
 210   }
 211   if (!params->source_contents && params->disposition == CURRENT_TAB)
 212     params->disposition = NEW_FOREGROUND_TAB;
 213
 214   switch (params->disposition) {
 215     case NEW_BACKGROUND_TAB:
 216       // Disposition trumps add types. ADD_ACTIVE is a default, so we need to
 217       // remove it if disposition implies the tab is going to open in the
 218       // background.
 219       params->tabstrip_add_types &= ~TabStripModel::ADD_ACTIVE;
 220       break;
 221
 222     case NEW_WINDOW:
 223     case NEW_POPUP:
 224       // Code that wants to open a new window typically expects it to be shown
 225       // automatically.
 226       if (params->window_action == chrome::NavigateParams::NO_ACTION)
 227         params->window_action = chrome::NavigateParams::SHOW_WINDOW;
 228       // Fall-through.
 229     case NEW_FOREGROUND_TAB:
 230     case SINGLETON_TAB:
 231       params->tabstrip_add_types |= TabStripModel::ADD_ACTIVE;
 232       break;
 233
 234     default:
 235       break;
 236   }
 237 }
 238
 239 // Obtain the profile used by the code that originated the Navigate() request.
 240 Profile* GetSourceProfile(chrome::NavigateParams* params) {
 241   if (params->source_contents) {
 242     return Profile::FromBrowserContext(
 243         params->source_contents->GetBrowserContext());
 244   }
 245
 246   return params->initiating_profile;
 247 }
 248
 249 void LoadURLInContents(WebContents* target_contents,
 250                        const GURL& url,
 251                        chrome::NavigateParams* params) {
 252   NavigationController::LoadURLParams load_url_params(url);
 253   load_url_params.referrer = params->referrer;
 254   load_url_params.frame_tree_node_id = params->frame_tree_node_id;
 255   load_url_params.redirect_chain = params->redirect_chain;
 256   load_url_params.transition_type = params->transition;
 257   load_url_params.extra_headers = params->extra_headers;
 258   load_url_params.should_replace_current_entry =
 259       params->should_replace_current_entry;
 260
 261   if (params->transferred_global_request_id != GlobalRequestID()) {
 262     load_url_params.is_renderer_initiated = params->is_renderer_initiated;
 263     load_url_params.transferred_global_request_id =
 264         params->transferred_global_request_id;
 265   } else if (params->is_renderer_initiated) {
 266     load_url_params.is_renderer_initiated = true;
 267   }
 268
 269   // Only allows the browser-initiated navigation to use POST.
 270   if (params->uses_post && !params->is_renderer_initiated) {
 271     load_url_params.load_type =
 272         NavigationController::LOAD_TYPE_BROWSER_INITIATED_HTTP_POST;
 273     load_url_params.browser_initiated_post_data =
 274         params->browser_initiated_post_data;
 275   }
 276   target_contents->GetController().LoadURLWithParams(load_url_params);
 277 }
 278
 279 // This class makes sure the Browser object held in |params| is made visible
 280 // by the time it goes out of scope, provided |params| wants it to be shown.
 281 class ScopedBrowserShower {
 282  public:
 283   explicit ScopedBrowserShower(chrome::NavigateParams* params)
 284       : params_(params) {
 285   }
 286   ~ScopedBrowserShower() {
 287     if (params_->window_action == chrome::NavigateParams::SHOW_WINDOW_INACTIVE)
 288       params_->browser->window()->ShowInactive();
 289     else if (params_->window_action == chrome::NavigateParams::SHOW_WINDOW)
 290       params_->browser->window()->Show();
 291   }
 292  private:
 293   chrome::NavigateParams* params_;
 294   DISALLOW_COPY_AND_ASSIGN(ScopedBrowserShower);
 295 };
 296
 297 // This class manages the lifetime of a WebContents created by the
 298 // Navigate() function. When Navigate() creates a WebContents for a URL,
 299 // an instance of this class takes ownership of it via TakeOwnership() until the
 300 // WebContents is added to a tab strip at which time ownership is
 301 // relinquished via ReleaseOwnership(). If this object goes out of scope without
 302 // being added to a tab strip, the created WebContents is deleted to
 303 // avoid a leak and the params->target_contents field is set to NULL.
 304 class ScopedTargetContentsOwner {
 305  public:
 306   explicit ScopedTargetContentsOwner(chrome::NavigateParams* params)
 307       : params_(params) {
 308   }
 309   ~ScopedTargetContentsOwner() {
 310     if (target_contents_owner_.get())
 311       params_->target_contents = NULL;
 312   }
 313
 314   // Assumes ownership of |params_|' target_contents until ReleaseOwnership
 315   // is called.
 316   void TakeOwnership() {
 317     target_contents_owner_.reset(params_->target_contents);
 318   }
 319
 320   // Relinquishes ownership of |params_|' target_contents.
 321   WebContents* ReleaseOwnership() {
 322     return target_contents_owner_.release();
 323   }
 324
 325  private:
 326   chrome::NavigateParams* params_;
 327   scoped_ptr<WebContents> target_contents_owner_;
 328   DISALLOW_COPY_AND_ASSIGN(ScopedTargetContentsOwner);
 329 };
 330
 331 content::WebContents* CreateTargetContents(const chrome::NavigateParams& params,
 332                                            const GURL& url) {
 333   WebContents::CreateParams create_params(
 334       params.browser->profile(),
 335       tab_util::GetSiteInstanceForNewTab(params.browser->profile(), url));
 336   if (params.source_contents) {
 337     create_params.initial_size =
 338         params.source_contents->GetView()->GetContainerSize();
 339     if (params.should_set_opener)
 340       create_params.opener = params.source_contents;
 341   }
 342   if (params.disposition == NEW_BACKGROUND_TAB)
 343     create_params.initially_hidden = true;
 344
 345 #if defined(USE_AURA)
 346   if (params.browser->window() &&
 347       params.browser->window()->GetNativeWindow()) {
 348     create_params.context =
 349         params.browser->window()->GetNativeWindow();
 350   }
 351 #endif
 352
 353   WebContents* target_contents = WebContents::Create(create_params);
 354
 355   // New tabs can have WebUI URLs that will make calls back to arbitrary
 356   // tab helpers, so the entire set of tab helpers needs to be set up
 357   // immediately.
 358   BrowserNavigatorWebContentsAdoption::AttachTabHelpers(target_contents);
 359   extensions::TabHelper::FromWebContents(target_contents)->
 360       SetExtensionAppById(params.extension_app_id);
 361   return target_contents;
 362 }
 363
 364 // If a prerendered page exists for |url|, replace the page at
 365 // |params->target_contents| with it and update to point to the swapped-in
 366 // WebContents.
 367 bool SwapInPrerender(const GURL& url, chrome::NavigateParams* params) {
 368   Profile* profile =
 369       Profile::FromBrowserContext(params->target_contents->GetBrowserContext());
 370   InstantSearchPrerenderer* prerenderer =
 371       InstantSearchPrerenderer::GetForProfile(profile);
 372   if (prerenderer && prerenderer->UsePrerenderedPage(url, params))
 373     return true;
 374
 375   prerender::PrerenderManager* prerender_manager =
 376       prerender::PrerenderManagerFactory::GetForProfile(profile);
 377   return prerender_manager &&
 378       prerender_manager->MaybeUsePrerenderedPage(url, params);
 379 }
 380
 381 chrome::HostDesktopType GetHostDesktop(Browser* browser) {
 382   if (browser)
 383     return browser->host_desktop_type();
 384   return chrome::GetActiveDesktop();
 385 }
 386
 387 }  // namespace
 388
 389 namespace chrome {
 390
 391 NavigateParams::NavigateParams(Browser* a_browser,
 392                                const GURL& a_url,
 393                                content::PageTransition a_transition)
 394     : url(a_url),
 395       frame_tree_node_id(-1),
 396       uses_post(false),
 397       target_contents(NULL),
 398       source_contents(NULL),
 399       disposition(CURRENT_TAB),
 400       transition(a_transition),
 401       is_renderer_initiated(false),
 402       tabstrip_index(-1),
 403       tabstrip_add_types(TabStripModel::ADD_ACTIVE),
 404       window_action(NO_ACTION),
 405       user_gesture(true),
 406       path_behavior(RESPECT),
 407       ref_behavior(IGNORE_REF),
 408       browser(a_browser),
 409       initiating_profile(NULL),
 410       host_desktop_type(GetHostDesktop(a_browser)),
 411       should_replace_current_entry(false),
 412       should_set_opener(false) {
 413 }
 414
 415 NavigateParams::NavigateParams(Browser* a_browser,
 416                                WebContents* a_target_contents)
 417     : frame_tree_node_id(-1),
 418       uses_post(false),
 419       target_contents(a_target_contents),
 420       source_contents(NULL),
 421       disposition(CURRENT_TAB),
 422       transition(content::PAGE_TRANSITION_LINK),
 423       is_renderer_initiated(false),
 424       tabstrip_index(-1),
 425       tabstrip_add_types(TabStripModel::ADD_ACTIVE),
 426       window_action(NO_ACTION),
 427       user_gesture(true),
 428       path_behavior(RESPECT),
 429       ref_behavior(IGNORE_REF),
 430       browser(a_browser),
 431       initiating_profile(NULL),
 432       host_desktop_type(GetHostDesktop(a_browser)),
 433       should_replace_current_entry(false),
 434       should_set_opener(false) {
 435 }
 436
 437 NavigateParams::NavigateParams(Profile* a_profile,
 438                                const GURL& a_url,
 439                                content::PageTransition a_transition)
 440     : url(a_url),
 441       frame_tree_node_id(-1),
 442       uses_post(false),
 443       target_contents(NULL),
 444       source_contents(NULL),
 445       disposition(NEW_FOREGROUND_TAB),
 446       transition(a_transition),
 447       is_renderer_initiated(false),
 448       tabstrip_index(-1),
 449       tabstrip_add_types(TabStripModel::ADD_ACTIVE),
 450       window_action(SHOW_WINDOW),
 451       user_gesture(true),
 452       path_behavior(RESPECT),
 453       ref_behavior(IGNORE_REF),
 454       browser(NULL),
 455       initiating_profile(a_profile),
 456       host_desktop_type(chrome::GetActiveDesktop()),
 457       should_replace_current_entry(false),
 458       should_set_opener(false) {
 459 }
 460
 461 NavigateParams::~NavigateParams() {}
 462
 463 void FillNavigateParamsFromOpenURLParams(chrome::NavigateParams* nav_params,
 464                                          const content::OpenURLParams& params) {
 465   nav_params->referrer = params.referrer;
 466   nav_params->frame_tree_node_id = params.frame_tree_node_id;
 467   nav_params->redirect_chain = params.redirect_chain;
 468   nav_params->extra_headers = params.extra_headers;
 469   nav_params->disposition = params.disposition;
 470   nav_params->is_renderer_initiated = params.is_renderer_initiated;
 471   nav_params->transferred_global_request_id =
 472       params.transferred_global_request_id;
 473   nav_params->should_replace_current_entry =
 474       params.should_replace_current_entry;
 475   nav_params->uses_post = params.uses_post;
 476   nav_params->browser_initiated_post_data = params.browser_initiated_post_data;
 477 }
 478
 479 void Navigate(NavigateParams* params) {
 480   Browser* source_browser = params->browser;
 481   if (source_browser)
 482     params->initiating_profile = source_browser->profile();
 483   DCHECK(params->initiating_profile);
 484
 485   if (!AdjustNavigateParamsForURL(params))
 486     return;
 487
 488   ExtensionService* service = params->initiating_profile->GetExtensionService();
 489   if (service)
 490     service->ShouldBlockUrlInBrowserTab(&params->url);
 491
 492   // The browser window may want to adjust the disposition.
 493   if (params->disposition == NEW_POPUP &&
 494       source_browser &&
 495       source_browser->window()) {
 496     params->disposition =
 497         source_browser->window()->GetDispositionForPopupBounds(
 498             params->window_bounds);
 499   }
 500
 501   params->browser = GetBrowserForDisposition(params);
 502   if (!params->browser)
 503     return;
 504
 505 #if defined(USE_ASH)
 506   if (source_browser && source_browser != params->browser) {
 507     // When the newly created browser was spawned by a browser which visits
 508     // another user's desktop, it should be shown on the same desktop as the
 509     // originating one. (This is part of the desktop separation per profile).
 510     MultiUserWindowManager* manager = MultiUserWindowManager::GetInstance();
 511     // Some unit tests have no manager instantiated.
 512     if (manager) {
 513       aura::Window* src_window = source_browser->window()->GetNativeWindow();
 514       aura::Window* new_window = params->browser->window()->GetNativeWindow();
 515       const std::string& src_user =
 516           manager->GetUserPresentingWindow(src_window);
 517       if (src_user != manager->GetUserPresentingWindow(new_window)) {
 518         // Once the window gets presented, it should be shown on the same
 519         // desktop as the desktop of the creating browser. Note that this
 520         // command will not show the window if it wasn't shown yet by the
 521         // browser creation.
 522         manager->ShowWindowForUser(new_window, src_user);
 523       }
 524     }
 525   }
 526 #endif
 527
 528   // Navigate() must not return early after this point.
 529
 530   if (GetSourceProfile(params) != params->browser->profile()) {
 531     // A tab is being opened from a link from a different profile, we must reset
 532     // source information that may cause state to be shared.
 533     params->source_contents = NULL;
 534     params->referrer = content::Referrer();
 535   }
 536
 537   // Make sure the Browser is shown if params call for it.
 538   ScopedBrowserShower shower(params);
 539
 540   // Makes sure any WebContents created by this function is destroyed if
 541   // not properly added to a tab strip.
 542   ScopedTargetContentsOwner target_contents_owner(params);
 543
 544   // Some dispositions need coercion to base types.
 545   NormalizeDisposition(params);
 546
 547   // If a new window has been created, it needs to be shown.
 548   if (params->window_action == NavigateParams::NO_ACTION &&
 549       source_browser != params->browser &&
 550       params->browser->tab_strip_model()->empty()) {
 551     params->window_action = NavigateParams::SHOW_WINDOW;
 552   }
 553
 554   // If we create a popup window from a non user-gesture, don't activate it.
 555   if (params->window_action == NavigateParams::SHOW_WINDOW &&
 556       params->disposition == NEW_POPUP &&
 557       params->user_gesture == false) {
 558     params->window_action = NavigateParams::SHOW_WINDOW_INACTIVE;
 559   }
 560
 561   // Determine if the navigation was user initiated. If it was, we need to
 562   // inform the target WebContents, and we may need to update the UI.
 563   content::PageTransition base_transition =
 564       content::PageTransitionStripQualifier(params->transition);
 565   bool user_initiated =
 566       params->transition & content::PAGE_TRANSITION_FROM_ADDRESS_BAR ||
 567       base_transition == content::PAGE_TRANSITION_TYPED ||
 568       base_transition == content::PAGE_TRANSITION_AUTO_BOOKMARK ||
 569       base_transition == content::PAGE_TRANSITION_GENERATED ||
 570       base_transition == content::PAGE_TRANSITION_AUTO_TOPLEVEL ||
 571       base_transition == content::PAGE_TRANSITION_RELOAD ||
 572       base_transition == content::PAGE_TRANSITION_KEYWORD;
 573
 574   // Check if this is a singleton tab that already exists
 575   int singleton_index = chrome::GetIndexOfSingletonTab(params);
 576
 577   // Did we use a prerender?
 578   bool swapped_in_prerender = false;
 579
 580   // If no target WebContents was specified, we need to construct one if
 581   // we are supposed to target a new tab; unless it's a singleton that already
 582   // exists.
 583   if (!params->target_contents && singleton_index < 0) {
 584     GURL url;
 585     if (params->url.is_empty()) {
 586       url = params->browser->profile()->GetHomePage();
 587       params->transition = content::PageTransitionFromInt(
 588           params->transition | content::PAGE_TRANSITION_HOME_PAGE);
 589     } else {
 590       url = params->url;
 591     }
 592
 593     if (params->disposition != CURRENT_TAB) {
 594       params->target_contents = CreateTargetContents(*params, url);
 595
 596       // This function takes ownership of |params->target_contents| until it
 597       // is added to a TabStripModel.
 598       target_contents_owner.TakeOwnership();
 599     } else {
 600       // ... otherwise if we're loading in the current tab, the target is the
 601       // same as the source.
 602       DCHECK(params->source_contents);
 603       params->target_contents = params->source_contents;
 604       DCHECK(params->target_contents);
 605       // Prerender expects |params->target_contents| to be attached to a browser
 606       // window, so only call for CURRENT_TAB navigations. (Others are currently
 607       // unsupported because of session storage namespaces anyway.)
 608       // Notice that this includes middle-clicking, since middle clicking
 609       // translates into a chrome::Navigate call with no URL followed by a
 610       // CURRENT_TAB navigation.
 611       // TODO(tburkard): We can actually swap in in non-CURRENT_TAB cases, as
 612       // long as the WebContents we swap into is part of a TabStrip model.
 613       // Therefore, we should swap in regardless of CURRENT_TAB, and instead,
 614       // check in the swapin function whether the WebContents is not in a
 615       // TabStrip model, in which case we must not swap in.
 616       swapped_in_prerender = SwapInPrerender(url, params);
 617     }
 618
 619     if (user_initiated)
 620       params->target_contents->UserGestureDone();
 621
 622     if (!swapped_in_prerender) {
 623       // Try to handle non-navigational URLs that popup dialogs and such, these
 624       // should not actually navigate.
 625       if (!HandleNonNavigationAboutURL(url)) {
 626         // Perform the actual navigation, tracking whether it came from the
 627         // renderer.
 628
 629         LoadURLInContents(params->target_contents, url, params);
 630         // For prerender bookkeeping purposes, record that this pending navigate
 631         // originated from chrome::Navigate.
 632         content::NavigationEntry* entry =
 633             params->target_contents->GetController().GetPendingEntry();
 634         if (entry)
 635           entry->SetExtraData(prerender::kChromeNavigateExtraDataKey,
 636                               base::string16());
 637       }
 638     }
 639   } else {
 640     // |target_contents| was specified non-NULL, and so we assume it has already
 641     // been navigated appropriately. We need to do nothing more other than
 642     // add it to the appropriate tabstrip.
 643   }
 644
 645   // If the user navigated from the omnibox, and the selected tab is going to
 646   // lose focus, then make sure the focus for the source tab goes away from the
 647   // omnibox.
 648   if (params->source_contents &&
 649       (params->disposition == NEW_FOREGROUND_TAB ||
 650        params->disposition == NEW_WINDOW) &&
 651       (params->tabstrip_add_types & TabStripModel::ADD_INHERIT_OPENER))
 652     params->source_contents->GetView()->Focus();
 653
 654   if (params->source_contents == params->target_contents ||
 655       (swapped_in_prerender && params->disposition == CURRENT_TAB)) {
 656     // The navigation occurred in the source tab.
 657     params->browser->UpdateUIForNavigationInTab(params->target_contents,
 658                                                 params->transition,
 659                                                 user_initiated);
 660   } else if (singleton_index == -1) {
 661     // If some non-default value is set for the index, we should tell the
 662     // TabStripModel to respect it.
 663     if (params->tabstrip_index != -1)
 664       params->tabstrip_add_types |= TabStripModel::ADD_FORCE_INDEX;
 665
 666     // The navigation should insert a new tab into the target Browser.
 667     params->browser->tab_strip_model()->AddWebContents(
 668         params->target_contents,
 669         params->tabstrip_index,
 670         params->transition,
 671         params->tabstrip_add_types);
 672     // Now that the |params->target_contents| is safely owned by the target
 673     // Browser's TabStripModel, we can release ownership.
 674     target_contents_owner.ReleaseOwnership();
 675   }
 676
 677   if (singleton_index >= 0) {
 678     WebContents* target =
 679         params->browser->tab_strip_model()->GetWebContentsAt(singleton_index);
 680
 681     if (target->IsCrashed()) {
 682       target->GetController().Reload(true);
 683     } else if (params->path_behavior == NavigateParams::IGNORE_AND_NAVIGATE &&
 684         target->GetURL() != params->url) {
 685       LoadURLInContents(target, params->url, params);
 686       // For prerender bookkeeping purposes, record that this pending navigate
 687       // originated from chrome::Navigate.
 688       content::NavigationEntry* entry =
 689           target->GetController().GetPendingEntry();
 690       if (entry)
 691         entry->SetExtraData(prerender::kChromeNavigateExtraDataKey,
 692                             base::string16());
 693     }
 694
 695     // If the singleton tab isn't already selected, select it.
 696     if (params->source_contents != params->target_contents) {
 697       params->browser->tab_strip_model()->ActivateTabAt(singleton_index,
 698                                                         user_initiated);
 699     }
 700   }
 701
 702   if (params->disposition != CURRENT_TAB) {
 703     content::NotificationService::current()->Notify(
 704         chrome::NOTIFICATION_TAB_ADDED,
 705         content::Source<content::WebContentsDelegate>(params->browser),
 706         content::Details<WebContents>(params->target_contents));
 707   }
 708 }
 709
 710 bool IsURLAllowedInIncognito(const GURL& url,
 711                              content::BrowserContext* browser_context) {
 712   if (url.scheme() == content::kViewSourceScheme) {
 713     // A view-source URL is allowed in incognito mode only if the URL itself
 714     // is allowed in incognito mode. Remove the "view-source:" from the start
 715     // of the URL and validate the rest.
 716     std::string stripped_spec = url.spec();
 717     DCHECK_GT(stripped_spec.size(), strlen(content::kViewSourceScheme));
 718     stripped_spec.erase(0, strlen(content::kViewSourceScheme) + 1);
 719     GURL stripped_url(stripped_spec);
 720     return stripped_url.is_valid() &&
 721         IsURLAllowedInIncognito(stripped_url, browser_context);
 722   }
 723   // Most URLs are allowed in incognito; the following are exceptions.
 724   // chrome://extensions is on the list because it redirects to
 725   // chrome://settings.
 726   if (url.scheme() == chrome::kChromeUIScheme &&
 727       (url.host() == chrome::kChromeUISettingsHost ||
 728        url.host() == chrome::kChromeUISettingsFrameHost ||
 729        url.host() == chrome::kChromeUIExtensionsHost ||
 730        url.host() == chrome::kChromeUIBookmarksHost ||
 731 #if defined(ENABLE_ENHANCED_BOOKMARKS)
 732        url.host() == chrome::kChromeUIEnhancedBookmarksHost ||
 733 #endif
 734 #if !defined(OS_CHROMEOS)
 735        url.host() == chrome::kChromeUIChromeSigninHost ||
 736 #endif
 737        url.host() == chrome::kChromeUIUberHost ||
 738        url.host() == chrome::kChromeUIThumbnailHost ||
 739        url.host() == chrome::kChromeUIThumbnailHost2 ||
 740        url.host() == chrome::kChromeUIThumbnailListHost)) {
 741     return false;
 742   }
 743
 744   if (url.scheme() == chrome::kChromeSearchScheme &&
 745       (url.host() == chrome::kChromeUIThumbnailHost ||
 746        url.host() == chrome::kChromeUIThumbnailHost2 ||
 747        url.host() == chrome::kChromeUIThumbnailListHost)) {
 748     return false;
 749   }
 750
 751   GURL rewritten_url = url;
 752   bool reverse_on_redirect = false;
 753   content::BrowserURLHandler::GetInstance()->RewriteURLIfNecessary(
 754       &rewritten_url, browser_context, &reverse_on_redirect);
 755
 756   // Some URLs are mapped to uber subpages. Do not allow them in incognito.
 757   return !(rewritten_url.scheme() == chrome::kChromeUIScheme &&
 758            rewritten_url.host() == chrome::kChromeUIUberHost);
 759 }
 760
 761 }  // namespace chrome