PlzNavigate: Clear provisional history item on redirects.

third_party/WebKit/Source/core/loader/FrameLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ skipping 337 matching lines @@
 
     // detachChildren() potentially detaches the frame from the document. The
     // loading cannot continue in that case.
     if (!m_frame->page())
         return;
 
     client()->transitionToCommittedForNewPage();
     documentLoader->replaceDocumentWhileExecutingJavaScriptURL(init, source);
 }
 
 void FrameLoader::receivedMainResourceRedirect(const KURL& newURL)

[Charlie Reis, 2016/08/09 05:07:31]

Can you explain why this doesn't get called in PlzNavigate but
WebDataSourceImpl::updateNavigation does?  I don't know as much about this part
of PlzNavigate.

[arthursonzogni, 2016/08/10 10:02:24]

With PlzNavigate enabled, the whole navigation, redirection included, is done
before the DocumentLoader is created. Thus,
DocumentLoader::receivedMainResourceRedirect is not called anymore.

The method DocumentLoader::updateNavigation is here to keep the internal
properties up-to-date (timings, redirect counts, ...), as if the navigation had
taken the old code path.

[Charlie Reis, 2016/08/11 21:05:01]

Acknowledged.

 {
     client()->dispatchDidReceiveServerRedirectForProvisionalLoad();
 
     // If a back/forward navigation redirects, don't reuse any state from the HistoryItem.
+    discardProvisionalHistoryItem();
+}
+
+void FrameLoader::discardProvisionalHistoryItem()
+{
     m_provisionalItem.clear();
 }
 
 void FrameLoader::setHistoryItemStateForCommit(FrameLoadType loadType, HistoryCommitType historyCommitType, HistoryNavigationType navigationType)
 {
     HistoryItem* oldItem = m_currentItem;
     if (isBackForwardLoadType(loadType) && m_provisionalItem)
         m_currentItem = m_provisionalItem.release();
     else
         m_currentItem = HistoryItem::create();
@@ skipping 1238 matching lines @@
     tracedValue->setString("documentLoaderURL", m_documentLoader ? m_documentLoader->url() : String());
     return tracedValue;
 }
 
 inline void FrameLoader::takeObjectSnapshot() const
 {
     TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID("loading", "FrameLoader", this, toTracedValue());
 }
 
 } // namespace blink