Always set the navigation pending item for page reload.

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 ccd31a039220858dec9b95c4540a465aae73177c..214cdc442f762e964c9f38a62e377a3193483ce9 100644
--- a/ios/web/web_state/ui/crw_web_controller.mm
+++ b/ios/web/web_state/ui/crw_web_controller.mm
@@ -1521,11 +1521,18 @@ registerLoadRequestForURL:(const GURL&)requestURL
     // Typically on PAGE_TRANSITION_CLIENT_REDIRECT.
     [[self sessionController] updatePendingItem:requestURL];
   } else {
-    // A new session history entry needs to be created.
-    self.navigationManagerImpl->AddPendingItem(
-        requestURL, referrer, transition,
-        web::NavigationInitiationType::RENDERER_INITIATED,
-        web::NavigationManager::UserAgentOverrideOption::INHERIT);
+    // If this is a reload then there no need to create a new pending item,
+    // instead update the pending item to the last committed item.
+    if (PageTransitionCoreTypeIs(transition, ui::PAGE_TRANSITION_RELOAD)) {
+      self.sessionController.pendingItemIndex =
+          self.sessionController.lastCommittedItemIndex;
+    } else {
+      // A new session history entry needs to be created.
+      self.navigationManagerImpl->AddPendingItem(
+          requestURL, referrer, transition,
+          web::NavigationInitiationType::RENDERER_INITIATED,
+          web::NavigationManager::UserAgentOverrideOption::INHERIT);
+    }
   }
   std::unique_ptr<web::NavigationContextImpl> context =
       web::NavigationContextImpl::CreateNavigationContext(
@@ -1988,6 +1995,11 @@ registerLoadRequestForURL:(const GURL&)requestURL
     BOOL isChromeScheme =
         web::GetWebClient()->IsAppSpecificURL(currentNavigationURL);
 
+    // Since this is implicit reload, no new pending item should be created, set
+    // the pending item index to the last committed item.
+    self.sessionController.pendingItemIndex =
+        self.sessionController.lastCommittedItemIndex;
+
     // Don't immediately load the web page if in overlay mode. Always load if
     // native.
     if (isChromeScheme || !_overlayPreviewMode) {
@@ -2029,6 +2041,10 @@ registerLoadRequestForURL:(const GURL&)requestURL
   _lastUserInteraction.reset();
   base::RecordAction(UserMetricsAction("Reload"));
   GURL url = self.currentNavItem->GetURL();
+  // Reloading shouldn't create create a new pending item, instead set the
+  // pending item index to the last committed item.
+  self.sessionController.pendingItemIndex =

[Eugene But (OOO till 7-30), 2017/06/15 00:08:11]

Wouldn't |reload| eventually call |registerLoadRequestForURL:| which also sets
pendingItemIndex? Or this code is really necessary?

[mrefaat, 2017/06/15 18:35:35]

This will not happen in every case, only when the the url is going to be open
natively not on web view.
I can move setting the pending item open in webview condition but i think this
is much simpler and easier to understand.

[Eugene But (OOO till 7-30), 2017/06/16 03:25:46]

Thanks. So this code is needed to cover NativeContent reload. 

But then how could it happen that Line 1527 can execute (Reload Transition and
no pending item)? 

[mrefaat, 2017/06/16 19:28:04]

This will happen in case the reload is triggered by the content itself not by
the browser.

[Eugene But (OOO till 7-30), 2017/06/17 02:57:14]

But reload triggered by renderer calls |reload| as well:
https://cs.chromium.org/chromium/src/ios/web/web_state/ui/crw_web_controller....

Did I miss something?

[mrefaat, 2017/06/17 11:33:08]

I'm not sure, from what i see it seems that goDelta is only called for history
forward/backward. and during my tests i have not passed through this function
once.

+      self.sessionController.lastCommittedItemIndex;
   if ([self shouldLoadURLInNativeView:url]) {
     std::unique_ptr<web::NavigationContextImpl> navigationContext = [self
         registerLoadRequestForURL:url