Ensure we don't crash if user navigates back from NTP to Chrome sign-in page before it has fully lo…

content/browser/web_contents/navigation_controller_impl.cc

 // Copyright (c) 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.
 
 #include "content/browser/web_contents/navigation_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"  // Temporary
@@ skipping 582 matching lines @@
   NavigateToPendingEntry(NO_RELOAD);
 }
 
 void NavigationControllerImpl::GoToOffset(int offset) {
   if (!CanGoToOffset(offset))
     return;
 
   GoToIndex(GetIndexForOffset(offset));
 }
 
-void NavigationControllerImpl::RemoveEntryAtIndex(int index) {
-  if (index == last_committed_entry_index_)
-    return;
+bool NavigationControllerImpl::RemoveEntryAtIndex(int index) {
+  if (index == last_committed_entry_index_ ||
+      index == pending_entry_index_)
+    return false;
 
   RemoveEntryAtIndexInternal(index);
+  return true;
 }
 
 void NavigationControllerImpl::UpdateVirtualURLToURL(
     NavigationEntryImpl* entry, const GURL& new_url) {
   GURL new_virtual_url(new_url);
   if (BrowserURLHandlerImpl::GetInstance()->ReverseURLRewrite(
           &new_virtual_url, entry->GetVirtualURL(), browser_context_)) {
     entry->SetVirtualURL(new_virtual_url);
   }
 }
@@ skipping 1064 matching lines @@
     }
   }
 }
 
 void NavigationControllerImpl::SetGetTimestampCallbackForTest(
     const base::Callback<base::Time()>& get_timestamp_callback) {
   get_timestamp_callback_ = get_timestamp_callback;
 }
 
 }  // namespace content