Reland of Set user agent type of transient item the same as pending item

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 da2ae03a14d715f438312e472af75142eecc141b..62522d968285026661f175552b6672759b354e61 100644
--- a/ios/web/navigation/navigation_manager_impl.mm
+++ b/ios/web/navigation/navigation_manager_impl.mm
@@ -170,6 +170,26 @@ bool AreURLsInPageNavigation(const GURL& existing_url, const GURL& new_url) {
   delegate_->GetWebState()->OpenURL(params);
 }
 
+void NavigationManagerImpl::AddTransientItem(const GURL& url) {
+  [session_controller_ addTransientItemWithURL:url];
+
+  // TODO(crbug.com/676129): Add a DCHECK that pending item should always exists
+  // when the bug is fixed, because transient item is only supposed to be added
+  // for pending non-app-specific loads.
+  if (GetPendingItem()) {

[Eugene But (OOO till 7-30), 2017/04/05 20:12:28]

Could you please avoid code duplication. Sothing like this:

NavigationItem* item = GetPendingItem();
// TODO: ...
if (!item) {
  item = GetLastCommittedNonAppSpecificItem();
}
GetTransientItem()->SetUserAgentType(item->GetUserAgentType());

[liaoyuke, 2017/04/05 20:29:40]

Done.

+    GetTransientItem()->SetUserAgentType(GetPendingItem()->GetUserAgentType());
+    return;
+  }
+
+  NavigationItem* last_non_native_item = GetLastCommittedNonAppSpecificItem();
+  DCHECK(!last_non_native_item ||
+         last_non_native_item->GetUserAgentType() != UserAgentType::NONE);
+  if (last_non_native_item) {
+    GetTransientItem()->SetUserAgentType(
+        last_non_native_item->GetUserAgentType());
+  }
+}
+
 void NavigationManagerImpl::AddPendingItem(
     const GURL& url,
     const web::Referrer& referrer,