[iOS] Refactoring web CRWSessionController user agent code.

ios/web/web_state/ui/crw_web_controller.mm

Index: ios/web/web_state/ui/crw_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_web_controller.mm b/ios/web/web_state/ui/crw_web_controller.mm
index 371ef69279882da8eb20b4ecd1cc1899c08f154f..32825e8cca466002c8523244a40d9cf9e8b5a858 100644
--- a/ios/web/web_state/ui/crw_web_controller.mm
+++ b/ios/web/web_state/ui/crw_web_controller.mm
@@ -1575,10 +1575,8 @@ - (void)registerLoadRequest:(const GURL&)requestURL
     [[self sessionController] updatePendingItem:requestURL];
   } else {
     // A new session history entry needs to be created.
-    [[self sessionController] addPendingItem:requestURL
-                                    referrer:referrer
-                                  transition:transition
-                           rendererInitiated:YES];
+    _webStateImpl->GetNavigationManagerImpl().AddRendererInitiatedPendingItem(
+        requestURL, referrer, transition);
   }
   _webStateImpl->SetIsLoading(true);
   _webStateImpl->OnProvisionalNavigationStarted(requestURL);
@@ -1912,14 +1910,17 @@ - (void)loadWithParams:(const NavigationManager::WebLoadParams&)originalParams {
     // forward/back transitions?
     [self recordStateInHistory];
 
-    CRWSessionController* history =
-        _webStateImpl->GetNavigationManagerImpl().GetSessionController();
     if (!self.currentSessionEntry)
       initialNavigation = YES;
-    [history addPendingItem:navUrl
-                   referrer:params.referrer
-                 transition:transition
-          rendererInitiated:params.is_renderer_initiated];
+
+    if (params.is_renderer_initiated) {
+      _webStateImpl->GetNavigationManagerImpl().AddRendererInitiatedPendingItem(

[Eugene But (OOO till 7-30), 2017/02/16 02:20:48]

Having 2 APIs for adding pendingItem looks error prone. How about creating a
enum inside navigation_manager_impl.h?:

class enum PendingItemType {
  USER_INITIATED = 1,
  RENDERER_INITIATED = 1,
};

[liaoyuke, 2017/02/16 22:04:29]

I like this idea, but I changed the class name to ItemInitiationType, which I
think is more informative. Please let me know if you don't like it.

[Eugene But (OOO till 7-30), 2017/02/17 00:00:23]

How about NavigationInitiationType ?

[Eugene But (OOO till 7-30), 2017/02/17 01:21:11]

Please address this comment.

[liaoyuke, 2017/02/17 01:58:45]

Agreed, NavigationInitiationType is more informative than ItemInitiationType.

+          navUrl, params.referrer, transition);
+    } else {
+      _webStateImpl->GetNavigationManagerImpl().AddUserInitiatedPendingItem(
+          navUrl, params.referrer, transition);
+    }
+
     web::NavigationItemImpl* addedItem =
         [self currentSessionEntry].navigationItemImpl;
     DCHECK(addedItem);