Implement Reload for ORIGINAL_REQUEST_URL in NavigationManagerImpl.

ios/web/navigation/navigation_manager_impl.mm

Index: ios/web/navigation/navigation_manager_impl.mm
diff --git a/ios/web/navigation/navigation_manager_impl.mm b/ios/web/navigation/navigation_manager_impl.mm
index 8d3ccad5d1c72df4f5f424ea43a86b2aae556e7f..bc867750778962db06457bcfab58d7b3b5ffec08 100644
--- a/ios/web/navigation/navigation_manager_impl.mm
+++ b/ios/web/navigation/navigation_manager_impl.mm
@@ -343,6 +343,43 @@ bool AreURLsInPageNavigation(const GURL& existing_url, const GURL& new_url) {
 
 void NavigationManagerImpl::Reload(ReloadType reload_type,
                                    bool check_for_reposts) {
+  // For request desktop/mobile site, we want to reload the page with the
+  // original request url of the last non-redirect item (including pending item)
+  // because a redirect may either change the url of the current item or add a
+  // new item. For example, an user visits www.youtube.com and is then
+  // redirected to m.youtube.com, so in this case, we want to request desktop
+  // version of www.youtube.com for the user instead of m.youtube.com.
+  if (reload_type == web::ReloadType::ORIGINAL_REQUEST_URL) {
+    web::UserAgentType type =
+        [session_controller_ currentItem]->GetUserAgentType();
+    web::NavigationItem* last_non_redirect_item = nullptr;
+
+    if (GetPendingItem() && ((GetPendingItem()->GetTransitionType() &
+                              ui::PAGE_TRANSITION_IS_REDIRECT_MASK) == 0)) {
+      last_non_redirect_item = GetPendingItem();
+    } else {
+      DiscardNonCommittedItems();
+      int index = GetLastCommittedItemIndex();
+      while (index >= 0) {
+        if (!IsRedirectItemAtIndex(index)) {
+          last_non_redirect_item = GetItemAtIndex(index);
+          break;
+        }
+
+        [session_controller_ goToItemAtIndex:(index - 1)];
+        bool item_removed_successfuly = RemoveItemAtIndex(index);
+        DCHECK(item_removed_successfuly);
+
+        --index;
+      }
+    }
+
+    DCHECK(last_non_redirect_item);
+    last_non_redirect_item->SetURL(
+        last_non_redirect_item->GetOriginalRequestURL());
+    last_non_redirect_item->SetUserAgentType(type);
+  }
+
   delegate_->Reload();
 }
 
@@ -438,7 +475,7 @@ bool AreURLsInPageNavigation(const GURL& existing_url, const GURL& new_url) {
 }
 
 bool NavigationManagerImpl::IsRedirectItemAtIndex(int index) const {
-  DCHECK_GT(index, 0);

[liaoyuke, 2017/03/22 23:46:23]

I don't see any reason why index cannot be 0. Am I missing something?

[Eugene But (OOO till 7-30), 2017/03/23 00:08:19]

This was a bug :)

+  DCHECK_GE(index, 0);
   DCHECK_LT(index, GetItemCount());
   ui::PageTransition transition = GetItemAtIndex(index)->GetTransitionType();
   return transition & ui::PAGE_TRANSITION_IS_REDIRECT_MASK;