Create new pending item if UserAgentOverrideOption is not INHERIT.

ios/web/navigation/crw_session_controller.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/web/navigation/crw_session_controller.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <utility>
@@ skipping 264 matching lines @@
   }
 }
 
 - (void)setBrowserState:(web::BrowserState*)browserState {
   _browserState = browserState;
   DCHECK(!_navigationManager ||
          _navigationManager->GetBrowserState() == _browserState);
 }
 
 - (void)addPendingItem:(const GURL&)url
-              referrer:(const web::Referrer&)ref
-            transition:(ui::PageTransition)trans
-        initiationType:(web::NavigationInitiationType)initiationType {
+                   referrer:(const web::Referrer&)ref
+                 transition:(ui::PageTransition)trans
+             initiationType:(web::NavigationInitiationType)initiationType
+    userAgentOverrideOption:(web::NavigationManager::UserAgentOverrideOption)
+                                userAgentOverrideOption {
   // Server side redirects are handled by updating existing pending item instead
   // of adding a new item.
   DCHECK((trans & ui::PAGE_TRANSITION_SERVER_REDIRECT) == 0);
 
   [self discardTransientItem];
   self.pendingItemIndex = -1;
 
   // Don't create a new item if it's already the same as the current item,
   // allowing this routine to be called multiple times in a row without issue.
   // Note: CRWSessionController currently has the responsibility to distinguish
   // between new navigations and history stack navigation, hence the inclusion
   // of specific transiton type logic here, in order to make it reliable with
   // real-world observed behavior.
   // TODO(crbug.com/676129): Fix the way changes are detected/reported elsewhere
   // in the web layer so that this hack can be removed.
   // Remove the workaround code from -presentSafeBrowsingWarningForResource:.
   web::NavigationItemImpl* currentItem = self.currentItem;
   if (currentItem) {
     BOOL hasSameURL = currentItem->GetURL() == url;
     BOOL isPendingTransitionFormSubmit =
         PageTransitionCoreTypeIs(trans, ui::PAGE_TRANSITION_FORM_SUBMIT);
     BOOL isCurrentTransitionFormSubmit = PageTransitionCoreTypeIs(
         currentItem->GetTransitionType(), ui::PAGE_TRANSITION_FORM_SUBMIT);
     BOOL shouldCreatePendingItem =
         !hasSameURL ||
         (isPendingTransitionFormSubmit && !isCurrentTransitionFormSubmit);
 
+    if (userAgentOverrideOption !=
+        web::NavigationManager::UserAgentOverrideOption::INHERIT)

[kkhorimoto, 2017/04/05 23:01:44]

I think we should also check whether the override option differs from the
current item's UA type so that we don't create new items that end up having the
same UA type as the previous item.  Also, can we define a separate bool after
|isCurrentTransitionFormSumbit| that checks this logic, then include it in the
|| statment where we define |shouldCreatePendingItem|?

[liaoyuke, 2017/04/06 22:24:55]

Theoretically, override option should always be different from current item's UI
type, so adding a DCHECK.

+      shouldCreatePendingItem = YES;
+
     if (!shouldCreatePendingItem) {
       // Send the notification anyway, to preserve old behavior. It's unknown
       // whether anything currently relies on this, but since both this whole
       // hack and the content facade will both be going away, it's not worth
       // trying to unwind.
       if (_navigationManager && _navigationManager->GetFacadeDelegate())
         _navigationManager->GetFacadeDelegate()->OnNavigationItemPending();
       return;
     }
   }
@@ skipping 304 matching lines @@
   return item;
 }
 
 - (BOOL)isRedirectTransitionForItemAtIndex:(size_t)index {
   DCHECK_LT(index, self.items.size());
   ui::PageTransition transition = self.items[index]->GetTransitionType();
   return (transition & ui::PAGE_TRANSITION_IS_REDIRECT_MASK) ? YES : NO;
 }
 
 @end