Eliminate webkit/glue/webhistoryitem* in favor of adding a

NavigateBackForwardSoon method WebViewDelegate.  This moves
all of the hacky details of how we intercept "history.{back,
forward,go}" into the webkit layer.  My eventual plan is to
teach WebCore how to make this not hacky.

BUG=11423
R=mpcomplete

Review URL: http://codereview.chromium.org/100353

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@15244 0039d316-1c4b-4281-b951-d872f2087c98

20 files changed, 87 insertions, 315 deletions

diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index 1236886..262997b 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -68,7 +68,6 @@
 #include "webkit/glue/webdropdata.h"
 #include "webkit/glue/weberror.h"
 #include "webkit/glue/webframe.h"
-#include "webkit/glue/webhistoryitem.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/glue/webpreferences.h"
 #include "webkit/glue/webplugin_delegate.h"
@@ -1553,13 +1552,6 @@ WindowOpenDisposition RenderView::DispositionForNavigationAction(
           url.SchemeIs(chrome::kViewSourceScheme)) {
         OpenURL(webview, url, GURL(), disposition);
         return IGNORE_ACTION;  // Suppress the load here.
-      } else if (url.SchemeIs(kBackForwardNavigationScheme)) {
-        std::string offset_str = url.ExtractFileName();
-        int offset;
-        if (StringToInt(offset_str, &offset)) {
-          GoToEntryAtOffset(offset);
-          return IGNORE_ACTION;  // The browser process handles this one.
-        }
       }
     }
   }
@@ -2433,20 +2425,7 @@ void RenderView::OnAutofillFormSubmitted(WebView* webview,
   Send(new ViewHostMsg_AutofillFormSubmitted(routing_id_, form));
 }
 
-WebHistoryItem* RenderView::GetHistoryEntryAtOffset(int offset) {
-  // Our history list is kept in the browser process on the UI thread.  Since
-  // we can't make a sync IPC call to that thread without risking deadlock,
-  // we use a trick: construct a fake history item of the form:
-  //   history://go/OFFSET
-  // When WebCore tells us to navigate to it, we tell the browser process to
-  // do a back/forward navigation instead.
-
-  GURL url(StringPrintf("%s://go/%d", kBackForwardNavigationScheme, offset));
-  history_navigation_item_ = WebHistoryItem::Create(url, L"", "", NULL);
-  return history_navigation_item_.get();
-}
-
-void RenderView::GoToEntryAtOffset(int offset) {
+void RenderView::NavigateBackForwardSoon(int offset) {
   history_back_list_count_ += offset;
   history_forward_list_count_ -= offset;
 
diff --git a/chrome/renderer/render_view.h b/chrome/renderer/render_view.h
index fa88cb1..fa28f0c 100644
--- a/chrome/renderer/render_view.h
+++ b/chrome/renderer/render_view.h
@@ -274,7 +274,7 @@ class RenderView : public RenderWidget,
   virtual void TakeFocus(WebView* webview, bool reverse);
   virtual void JSOutOfMemory();
 
-  virtual WebHistoryItem* GetHistoryEntryAtOffset(int offset);
+  virtual void NavigateBackForwardSoon(int offset);
   virtual int GetHistoryBackListCount();
   virtual int GetHistoryForwardListCount();
   virtual void OnNavStateChanged(WebView* webview);
@@ -453,10 +453,6 @@ class RenderView : public RenderWidget,
   // Update the feed list.
   void UpdateFeedList(scoped_refptr<FeedList> feedlist);
 
-  // Tells the browser process to navigate to a back/forward entry at the given
-  // offset from current.
-  void GoToEntryAtOffset(int offset);
-
   // RenderView IPC message handlers
   void SendThumbnail();
   void OnPrintPages();
@@ -763,11 +759,6 @@ class RenderView : public RenderWidget,
   // out of date responses.
   int form_field_autofill_request_id_;
 
-  // A cached WebHistoryItem used for back/forward navigations initiated by
-  // WebCore (via the window.history.go API).  We only have one such navigation
-  // pending at a time.
-  scoped_refptr<WebHistoryItem> history_navigation_item_;
-
   // We need to prevent windows from closing themselves with a window.close()
   // call while a blocked popup notification is being displayed. We cannot
   // synchronously querry the Browser process. We cannot wait for the Browser
diff --git a/webkit/glue/back_forward_list_client_impl.cc b/webkit/glue/back_forward_list_client_impl.cc
index 99149d1..ec24804 100644
--- a/webkit/glue/back_forward_list_client_impl.cc
+++ b/webkit/glue/back_forward_list_client_impl.cc
@@ -8,11 +8,12 @@
 #undef LOG
 
 #include "webkit/glue/back_forward_list_client_impl.h"
-#include "webkit/glue/webhistoryitem_impl.h"
 #include "webkit/glue/webview_impl.h"
 
 namespace webkit_glue {
 
+const char kBackForwardNavigationScheme[] = "chrome-back-forward";
+
 BackForwardListClientImpl::BackForwardListClientImpl(WebViewImpl* webview)
     : webview_(webview) {
 }
@@ -47,15 +48,8 @@ void BackForwardListClientImpl::goToItem(WebCore::HistoryItem* item) {
   previous_item_ = current_item_;
   current_item_ = item;
 
-  if (pending_history_item_) {
-    if (item == pending_history_item_->GetHistoryItem()) {
-      // Let the main frame know this HistoryItem is loading, so it can cache
-      // any ExtraData when the DataSource is created.
-      webview_->main_frame()->set_currently_loading_history_item(
-          pending_history_item_);
-      pending_history_item_ = NULL;
-    }
-  }
+  if (pending_history_item_ == item)
+    pending_history_item_ = NULL;
 }
 
 WebCore::HistoryItem* BackForwardListClientImpl::currentItem() {
@@ -66,14 +60,21 @@ WebCore::HistoryItem* BackForwardListClientImpl::itemAtIndex(int index) {
   if (!webview_->delegate())
     return NULL;
 
-  WebHistoryItem* item = webview_->delegate()->GetHistoryEntryAtOffset(index);
-  if (!item)
-    return NULL;
+  // Since we don't keep the entire back/forward list, we have no way to
+  // properly implement this method.  We return a dummy entry instead that we
+  // intercept in our FrameLoaderClient implementation in case WebCore asks
+  // to navigate to this HistoryItem.
+
+  // TODO(darin): We should change WebCore to handle history.{back,forward,go}
+  // differently.  It should perhaps just ask the FrameLoaderClient to perform
+  // those navigations.
+
+  WebCore::String url_string = WebCore::String::format(
+      "%s://go/%d", kBackForwardNavigationScheme, index);
 
-  // If someone has asked for a history item, we probably want to navigate to
-  // it soon.  Keep track of it until goToItem is called.
-  pending_history_item_ = static_cast<WebHistoryItemImpl*>(item);
-  return pending_history_item_->GetHistoryItem();
+  pending_history_item_ =
+      WebCore::HistoryItem::create(url_string, WebCore::String(), 0.0);
+  return pending_history_item_.get();
 }
 
 int BackForwardListClientImpl::backListCount() {
diff --git a/webkit/glue/back_forward_list_client_impl.h b/webkit/glue/back_forward_list_client_impl.h
index 1a26c35..45ad379 100644
--- a/webkit/glue/back_forward_list_client_impl.h
+++ b/webkit/glue/back_forward_list_client_impl.h
@@ -9,11 +9,12 @@
 
 #include "base/ref_counted.h"
 
-class WebHistoryItemImpl;
 class WebViewImpl;
 
 namespace webkit_glue {
 
+extern const char kBackForwardNavigationScheme[];
+
 class BackForwardListClientImpl : public WebCore::BackForwardListClient {
  public:
   BackForwardListClientImpl(WebViewImpl* webview);
@@ -39,7 +40,7 @@ class BackForwardListClientImpl : public WebCore::BackForwardListClient {
 
   // The last history item that was accessed via itemAtIndex().  We keep track
   // of this until goToItem() is called, so we can track the navigation.
-  scoped_refptr<WebHistoryItemImpl> pending_history_item_;
+  RefPtr<WebCore::HistoryItem> pending_history_item_;
 };
 
 } // namespace webkit_glue
diff --git a/webkit/glue/glue.vcproj b/webkit/glue/glue.vcproj
index 0677fbb..f16606e 100644
--- a/webkit/glue/glue.vcproj
+++ b/webkit/glue/glue.vcproj
@@ -222,10 +222,6 @@
 				>

 			</File>

 			<File

-				RelativePath=".\webhistoryitem.h"

-				>

-			</File>

-			<File

 				RelativePath=".\webmediaplayer.h"

 				>

 			</File>

@@ -642,14 +638,6 @@
 				>

 			</File>

 			<File

-				RelativePath=".\webhistoryitem_impl.cc"

-				>

-			</File>

-			<File

-				RelativePath=".\webhistoryitem_impl.h"

-				>

-			</File>

-			<File

 				RelativePath=".\webkit_glue.cc"

 				>

 			</File>

diff --git a/webkit/glue/webframe_impl.cc b/webkit/glue/webframe_impl.cc
index 3b87d4f..46faf37 100644
--- a/webkit/glue/webframe_impl.cc
+++ b/webkit/glue/webframe_impl.cc
@@ -150,7 +150,6 @@ MSVC_POP_WARNING();
 #include "webkit/glue/webdatasource_impl.h"
 #include "webkit/glue/weberror_impl.h"
 #include "webkit/glue/webframe_impl.h"
-#include "webkit/glue/webhistoryitem_impl.h"
 #include "webkit/glue/weburlrequest_impl.h"
 #include "webkit/glue/webtextinput_impl.h"
 #include "webkit/glue/webview_impl.h"
@@ -714,25 +713,15 @@ void WebFrameImpl::CacheCurrentRequestInfo(WebDataSourceImpl* datasource) {
   // own requests, so the extra data needs to be transferred.
   scoped_refptr<WebRequest::ExtraData> extra;
 
-  // Our extra data may come from a request issued via LoadRequest, or a
-  // history navigation from WebCore.
-  if (currently_loading_request_) {
+  // Our extra data may come from a request issued via LoadRequest.
+  if (currently_loading_request_)
     extra = currently_loading_request_->GetExtraData();
-  } else if (currently_loading_history_item_) {
-    extra = currently_loading_history_item_->GetExtraData();
-    currently_loading_history_item_ = 0;
-  }
 
   // We must only update this if it is valid, or the valid state will be lost.
   if (extra)
     datasource->SetExtraData(extra);
 }
 
-void WebFrameImpl::set_currently_loading_history_item(
-    WebHistoryItemImpl* item) {
-  currently_loading_history_item_ = item;
-}
-
 void WebFrameImpl::StopLoading() {
   if (!frame_)
     return;
diff --git a/webkit/glue/webframe_impl.h b/webkit/glue/webframe_impl.h
index 61162f7..e8abb8b 100644
--- a/webkit/glue/webframe_impl.h
+++ b/webkit/glue/webframe_impl.h
@@ -43,7 +43,6 @@ class AltErrorPageResourceFetcher;
 class ChromePrintContext;
 class WebDataSourceImpl;
 class WebErrorImpl;
-class WebHistoryItemImpl;
 class WebPluginDelegate;
 class WebRequest;
 class WebView;
@@ -229,8 +228,6 @@ class WebFrameImpl : public WebFrame, public base::RefCounted<WebFrameImpl> {
   // If currently_loading_request is NULL, does nothing.
   void CacheCurrentRequestInfo(WebDataSourceImpl* datasource);
 
-  void set_currently_loading_history_item(WebHistoryItemImpl* item);
-
   // Getters for the impls corresponding to Get(Provisional)DataSource. They
   // may return NULL if there is no corresponding data source.
   WebDataSourceImpl* GetDataSourceImpl() const;
@@ -316,10 +313,6 @@ class WebFrameImpl : public WebFrame, public base::RefCounted<WebFrameImpl> {
   // information to him.  Only non-NULL during a call to LoadRequest.
   const WebRequest* currently_loading_request_;
 
-  // Similar to currently_loading_request_, except this will be set when
-  // WebCore initiates a history navigation (probably via javascript).
-  scoped_refptr<WebHistoryItemImpl> currently_loading_history_item_;
-
   // Plugins sometimes need to be notified when loads are complete so we keep
   // a pointer back to the appropriate plugin.
   WebPluginDelegate* plugin_delegate_;
diff --git a/webkit/glue/webframeloaderclient_impl.cc b/webkit/glue/webframeloaderclient_impl.cc
index b2cdae9..4c66be2a 100644
--- a/webkit/glue/webframeloaderclient_impl.cc
+++ b/webkit/glue/webframeloaderclient_impl.cc
@@ -55,7 +55,6 @@ MSVC_POP_WARNING();
 #include "webkit/glue/webdevtoolsagent_impl.h"
 #include "webkit/glue/weberror_impl.h"
 #include "webkit/glue/webframeloaderclient_impl.h"
-#include "webkit/glue/webhistoryitem_impl.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/glue/webplugin_impl.h"
 #include "webkit/glue/webresponse_impl.h"
@@ -786,16 +785,6 @@ void WebFrameLoaderClient::dispatchDidStartProvisionalLoad() {
     alt_404_page_fetcher_->Cancel();
 }
 
-NavigationGesture WebFrameLoaderClient::NavigationGestureForLastLoad() {
-  // TODO(timsteele): userGestureHint returns too many false positives
-  // (see bug 1051891) to trust it and assign NavigationGestureUser, so
-  // for now we assign Unknown in those cases and Auto otherwise.
-  // (Issue 874811 known false negative as well).
-  return webframe_->frame()->loader()->userGestureHint() ?
-      NavigationGestureUnknown :
-      NavigationGestureAuto;
-}
-
 void WebFrameLoaderClient::dispatchDidReceiveTitle(const String& title) {
   WebViewImpl* webview = webframe_->webview_impl();
   WebViewDelegate* d = webview->delegate();
@@ -1020,13 +1009,19 @@ void WebFrameLoaderClient::dispatchDecidePolicyForNavigationAction(
     // such navigations.
     const WebDataSourceImpl* ds = webframe_->GetProvisionalDataSourceImpl();
     if (ds) {
-      bool is_redirect = !ds->GetRedirectChain().empty();
+      const GURL& url = ds->GetRequest().GetURL();
+      if (url.SchemeIs(webkit_glue::kBackForwardNavigationScheme)) {
+        HandleBackForwardNavigation(url);
+        disposition = IGNORE_ACTION;
+      } else {
+        bool is_redirect = !ds->GetRedirectChain().empty();
 
-      WebNavigationType webnav_type =
-          WebDataSourceImpl::NavigationTypeToWebNavigationType(action.type());
+        WebNavigationType webnav_type =
+            WebDataSourceImpl::NavigationTypeToWebNavigationType(action.type());
 
-      disposition = d->DispositionForNavigationAction(
-          wv, webframe_, &ds->GetRequest(), webnav_type, disposition, is_redirect);
+        disposition = d->DispositionForNavigationAction(
+            wv, webframe_, &ds->GetRequest(), webnav_type, disposition, is_redirect);
+      }
 
       if (disposition != IGNORE_ACTION) {
         if (disposition == CURRENT_TAB) {
@@ -1635,6 +1630,29 @@ bool WebFrameLoaderClient::ActionSpecifiesDisposition(
   return true;
 }
 
+NavigationGesture WebFrameLoaderClient::NavigationGestureForLastLoad() {
+  // TODO(timsteele): userGestureHint returns too many false positives
+  // (see bug 1051891) to trust it and assign NavigationGestureUser, so
+  // for now we assign Unknown in those cases and Auto otherwise.
+  // (Issue 874811 known false negative as well).
+  return webframe_->frame()->loader()->userGestureHint() ?
+      NavigationGestureUnknown :
+      NavigationGestureAuto;
+}
+
+void WebFrameLoaderClient::HandleBackForwardNavigation(const GURL& url) {
+  DCHECK(url.SchemeIs(webkit_glue::kBackForwardNavigationScheme));
+
+  std::string offset_str = url.ExtractFileName();
+  int offset;
+  if (!StringToInt(offset_str, &offset))
+    return;
+
+  WebViewDelegate* d = webframe_->webview_impl()->delegate();
+  if (d)
+    d->NavigateBackForwardSoon(offset);
+}
+
 NetAgentImpl* WebFrameLoaderClient::GetNetAgentImpl() {
   WebViewImpl* web_view = webframe_->webview_impl();
   if (!web_view) {
diff --git a/webkit/glue/webframeloaderclient_impl.h b/webkit/glue/webframeloaderclient_impl.h
index ec51ea8..f616aee 100644
--- a/webkit/glue/webframeloaderclient_impl.h
+++ b/webkit/glue/webframeloaderclient_impl.h
@@ -220,6 +220,9 @@ class WebFrameLoaderClient : public WebCore::FrameLoaderClient {
   // otherwise returns NavigationGestureUnknown.
   NavigationGesture NavigationGestureForLastLoad();
 
+  // Called when a dummy back-forward navigation is intercepted.
+  void HandleBackForwardNavigation(const GURL&);
+
   // Returns NetAgent instance if network tracking is enabled.
   NetAgentImpl* GetNetAgentImpl();
 
diff --git a/webkit/glue/webhistoryitem.h b/webkit/glue/webhistoryitem.h
deleted file mode 100644
index 6757211..0000000
--- a/webkit/glue/webhistoryitem.h
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright (c) 2006-2008 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.
-
-#ifndef WEBKIT_GLUE_WEBHISTORYITEM_H_
-#define WEBKIT_GLUE_WEBHISTORYITEM_H_
-
-#include "webkit/glue/weburlrequest.h"  // for WebRequest::ExtraData
-
-class GURL;
-
-class WebHistoryItem : public base::RefCounted<WebHistoryItem> {
- public:
-  // Create a new history item.
-  static WebHistoryItem* Create(const GURL& url,
-                                const std::wstring& title,
-                                const std::string& history_state,
-                                WebRequest::ExtraData* extra_data);
-
-  WebHistoryItem() { }
-  virtual ~WebHistoryItem() { }
-
-  // Returns the URL.
-  virtual const GURL& GetURL() const = 0;
-
-  // Returns the title.
-  virtual const std::wstring& GetTitle() const = 0;
-
-  // Returns the string representation of the history state for this entry.
-  virtual const std::string& GetHistoryState() const = 0;
-
-  // Returns any ExtraData associated with this history entry.
-  virtual WebRequest::ExtraData* GetExtraData() const = 0;
-
- private:
-  DISALLOW_EVIL_CONSTRUCTORS(WebHistoryItem);
-};
-
-#endif  // #ifndef WEBKIT_GLUE_WEBHISTORYITEM_H_
diff --git a/webkit/glue/webhistoryitem_impl.cc b/webkit/glue/webhistoryitem_impl.cc
deleted file mode 100644
index c381eed..0000000
--- a/webkit/glue/webhistoryitem_impl.cc
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "webkit/glue/webhistoryitem_impl.h"
-
-#include "webkit/glue/glue_serialize.h"
-#include "webkit/glue/glue_util.h"
-
-#include "base/compiler_specific.h"
-
-MSVC_PUSH_WARNING_LEVEL(0);
-#include "HistoryItem.h"
-MSVC_POP_WARNING();
-
-
-WebHistoryItem* WebHistoryItem::Create(const GURL& url,
-                                       const std::wstring& title,
-                                       const std::string& history_state,
-                                       WebRequest::ExtraData* extra_data) {
-  return new WebHistoryItemImpl(url, title, history_state, extra_data);
-}
-
-WebHistoryItemImpl::WebHistoryItemImpl(const GURL& url,
-                                       const std::wstring& title,
-                                       const std::string& history_state,
-                                       WebRequest::ExtraData* extra_data) :
-    url_(url),
-    title_(title),
-    history_state_(history_state),
-    history_item_(NULL),
-    extra_data_(extra_data) {
-}
-
-WebHistoryItemImpl::~WebHistoryItemImpl() {
-}
-
-const std::wstring& WebHistoryItemImpl::GetTitle() const {
-  return title_;
-}
-
-const std::string& WebHistoryItemImpl::GetHistoryState() const {
-  return history_state_;
-}
-
-WebRequest::ExtraData* WebHistoryItemImpl::GetExtraData() const {
-  return extra_data_.get();
-}
-
-WebCore::HistoryItem* WebHistoryItemImpl::GetHistoryItem() const {
-  if (history_item_)
-    return history_item_.get();
-
-  if (history_state_.size() > 0) {
-    history_item_ = webkit_glue::HistoryItemFromString(history_state_);
-  } else {
-    history_item_ = WebCore::HistoryItem::create(
-      webkit_glue::StdStringToString(url_.spec()),
-      webkit_glue::StdWStringToString(title_),
-      0.0);
-  }
-
-  return history_item_.get();
-}
-
-const GURL& WebHistoryItemImpl::GetURL() const {
-  return url_;
-}
diff --git a/webkit/glue/webhistoryitem_impl.h b/webkit/glue/webhistoryitem_impl.h
deleted file mode 100644
index b28fb91..0000000
--- a/webkit/glue/webhistoryitem_impl.h
+++ /dev/null
@@ -1,47 +0,0 @@
-// Copyright (c) 2006-2008 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.
-
-#ifndef WEBKIT_GLUE_WEBHISTORYITEM_IMPL_H_
-#define WEBKIT_GLUE_WEBHISTORYITEM_IMPL_H_
-
-#include "webkit/glue/webhistoryitem.h"
-#include "googleurl/src/gurl.h"
-
-#include "RefPtr.h"
-
-namespace WebCore {
-  class HistoryItem;
-}
-
-class WebHistoryItemImpl : public WebHistoryItem {
- public:
-  WebHistoryItemImpl(const GURL& url,
-                     const std::wstring& title,
-                     const std::string& history_state,
-                     WebRequest::ExtraData* extra_data);
-  virtual ~WebHistoryItemImpl();
-
-  // WebHistoryItem
-  virtual const GURL& GetURL() const;
-  virtual const std::wstring& GetTitle() const;
-  virtual const std::string& GetHistoryState() const;
-  virtual WebRequest::ExtraData* GetExtraData() const;
-
-  // WebHistoryItemImpl
-  // Returns a WebCore::HistoryItem based on the history_state.  This is
-  // lazily-created and cached.
-  WebCore::HistoryItem* GetHistoryItem() const;
-
- protected:
-  GURL url_;
-  std::wstring title_;
-  std::string history_state_;
-  mutable RefPtr<WebCore::HistoryItem> history_item_;
-  scoped_refptr<WebRequest::ExtraData> extra_data_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(WebHistoryItemImpl);
-};
-
-#endif  // #ifndef WEBKIT_GLUE_WEBHISTORYITEM_IMPL_H_
diff --git a/webkit/glue/webview_delegate.h b/webkit/glue/webview_delegate.h
index 27036db..483ef1c 100644
--- a/webkit/glue/webview_delegate.h
+++ b/webkit/glue/webview_delegate.h
@@ -53,7 +53,6 @@ class SkBitmap;
 class WebDevToolsAgentDelegate;
 class WebError;
 class WebFrame;
-class WebHistoryItem;
 class WebMediaPlayerDelegate;
 class WebPluginDelegate;
 class WebRequest;
@@ -695,10 +694,9 @@ class WebViewDelegate : virtual public WebWidgetDelegate {
 
   // History Related ---------------------------------------------------------
 
-  // Returns the session history entry at a distance |offset| relative to the
-  // current entry.  Returns NULL on failure.
-  virtual WebHistoryItem* GetHistoryEntryAtOffset(int offset) {
-    return NULL;
+  // Tells the embedder to navigate back or forward in session history by the
+  // given offset (relative to the current position in session history).
+  virtual void NavigateBackForwardSoon(int offset) {
   }
 
   // Returns how many entries are in the back and forward lists, respectively.
diff --git a/webkit/glue/webview_impl.cc b/webkit/glue/webview_impl.cc
index 7e41aa9..e4fd16d 100644
--- a/webkit/glue/webview_impl.cc
+++ b/webkit/glue/webview_impl.cc
@@ -100,7 +100,6 @@ MSVC_POP_WARNING();
 #include "webkit/glue/searchable_form_data.h"
 #include "webkit/glue/webdevtoolsagent_impl.h"
 #include "webkit/glue/webdropdata.h"
-#include "webkit/glue/webhistoryitem_impl.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/glue/webpreferences.h"
 #include "webkit/glue/webdevtoolsagent.h"
diff --git a/webkit/tools/test_shell/test_navigation_controller.cc b/webkit/tools/test_shell/test_navigation_controller.cc
index ff4a753..cf26baf 100644
--- a/webkit/tools/test_shell/test_navigation_controller.cc
+++ b/webkit/tools/test_shell/test_navigation_controller.cc
@@ -5,7 +5,6 @@
 #include "webkit/tools/test_shell/test_navigation_controller.h"
 
 #include "base/logging.h"
-#include "webkit/glue/webhistoryitem.h"
 #include "webkit/tools/test_shell/test_shell.h"
 
 // ----------------------------------------------------------------------------
@@ -29,21 +28,9 @@ TestNavigationEntry::~TestNavigationEntry() {
 }
 
 void TestNavigationEntry::SetContentState(const std::string& state) {
-  cached_history_item_ = NULL;  // invalidate our cached item
   state_ = state;
 }
 
-WebHistoryItem* TestNavigationEntry::GetHistoryItem() const {
-  if (!cached_history_item_) {
-    TestShellExtraRequestData* extra_data =
-        new TestShellExtraRequestData(GetPageID());
-    cached_history_item_ =
-        WebHistoryItem::Create(GetURL(), GetTitle(), GetContentState(),
-                               extra_data);
-  }
-  return cached_history_item_;
-}
-
 // ----------------------------------------------------------------------------
 // TestNavigationController
 
diff --git a/webkit/tools/test_shell/test_navigation_controller.h b/webkit/tools/test_shell/test_navigation_controller.h
index 07f42f8..e24fff30 100644
--- a/webkit/tools/test_shell/test_navigation_controller.h
+++ b/webkit/tools/test_shell/test_navigation_controller.h
@@ -16,7 +16,6 @@
 
 class GURL;
 class TestShell;
-class WebHistoryItem;
 
 // Associated with browser-initated navigations to hold tracking data.
 class TestShellExtraRequestData : public WebRequest::ExtraData {
@@ -67,7 +66,6 @@ class TestNavigationEntry {
   void SetPageID(int page_id) { page_id_ = page_id; }
   int32 GetPageID() const { return page_id_; }
 
-  WebHistoryItem* GetHistoryItem() const;
   const std::wstring& GetTargetFrame() const { return target_frame_; }
 
  private:
@@ -79,8 +77,6 @@ class TestNavigationEntry {
   std::wstring title_;
   std::string state_;
 
-  mutable scoped_refptr<WebHistoryItem> cached_history_item_;
-
   std::wstring target_frame_;
 
   DISALLOW_COPY_AND_ASSIGN(TestNavigationEntry);
diff --git a/webkit/tools/test_shell/test_shell.cc b/webkit/tools/test_shell/test_shell.cc
index 96a5ca5..3f88d26 100755
--- a/webkit/tools/test_shell/test_shell.cc
+++ b/webkit/tools/test_shell/test_shell.cc
@@ -125,6 +125,7 @@ TestShell::~TestShell() {
   CallJSGC();
   CallJSGC();
 
+  delegate_->clear_test_shell();
   webView()->SetDelegate(NULL);
   PlatformCleanUp();
 
diff --git a/webkit/tools/test_shell/test_webview_delegate.cc b/webkit/tools/test_shell/test_webview_delegate.cc
index 4bf5601..c891c79 100755
--- a/webkit/tools/test_shell/test_webview_delegate.cc
+++ b/webkit/tools/test_shell/test_webview_delegate.cc
@@ -114,6 +114,14 @@ WebWidget* TestWebViewDelegate::CreatePopupWidget(WebView* webview,
   return shell_->CreatePopupWidget(webview);
 }
 
+WebWorker* TestWebViewDelegate::CreateWebWorker(WebWorkerClient* client) {
+#if ENABLE(WORKERS)
+  return TestWebWorkerHelper::CreateWebWorker(client);
+#else
+  return NULL;
+#endif
+}
+
 void TestWebViewDelegate::OpenURL(WebView* webview, const GURL& url,
                                   const GURL& referrer,
                                   WindowOpenDisposition disposition) {
@@ -660,13 +668,11 @@ void TestWebViewDelegate::DidEndEditing() {
   }
 }
 
-WebHistoryItem* TestWebViewDelegate::GetHistoryEntryAtOffset(int offset) {
-  TestNavigationEntry* entry = static_cast<TestNavigationEntry*>(
-      shell_->navigation_controller()->GetEntryAtOffset(offset));
-  if (!entry)
-    return NULL;
-
-  return entry->GetHistoryItem();
+void TestWebViewDelegate::NavigateBackForwardSoon(int offset) {
+  // We start this navigation via a delayed task to match Chrome's asynchronous
+  // implementation of this method.
+  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
+      this, &TestWebViewDelegate::NavigateBackForward, offset));
 }
 
 int TestWebViewDelegate::GetHistoryBackListCount() {
@@ -888,10 +894,7 @@ std::wstring TestWebViewDelegate::GetFrameDescription(WebFrame* webframe) {
   }
 }
 
-WebWorker* TestWebViewDelegate::CreateWebWorker(WebWorkerClient* client) {
-#if ENABLE(WORKERS)
-  return TestWebWorkerHelper::CreateWebWorker(client);
-#else
-  return NULL;
-#endif
+void TestWebViewDelegate::NavigateBackForward(int offset) {
+  if (shell_)
+    shell_->navigation_controller()->GoToOffset(offset);
 }
diff --git a/webkit/tools/test_shell/test_webview_delegate.h b/webkit/tools/test_shell/test_webview_delegate.h
index 79fd25d..d6e1001 100644
--- a/webkit/tools/test_shell/test_webview_delegate.h
+++ b/webkit/tools/test_shell/test_webview_delegate.h
@@ -205,7 +205,7 @@ class TestWebViewDelegate : public base::RefCounted<TestWebViewDelegate>,
     WebNavigationType type,
     WindowOpenDisposition disposition,
     bool is_redirect);
-  virtual WebHistoryItem* GetHistoryEntryAtOffset(int offset);
+  virtual void NavigateBackForwardSoon(int offset);
   virtual int GetHistoryBackListCount();
   virtual int GetHistoryForwardListCount();
 
@@ -269,6 +269,8 @@ class TestWebViewDelegate : public base::RefCounted<TestWebViewDelegate>,
   void SetCustomPolicyDelegate(bool is_custom, bool is_permissive);
   void WaitForPolicyDelegate();
 
+  void clear_test_shell() { shell_ = NULL; }
+
  protected:
   // Called the title of the page changes.
   // Can be used to update the title of the window.
@@ -302,6 +304,8 @@ class TestWebViewDelegate : public base::RefCounted<TestWebViewDelegate>,
   // Get a string suitable for dumping a frame to the console.
   std::wstring GetFrameDescription(WebFrame* webframe);
 
+  void NavigateBackForward(int offset);
+
  private:
   // Causes navigation actions just printout the intended navigation instead
   // of taking you to the page. This is used for cases like mailto, where you
diff --git a/webkit/webkit.gyp b/webkit/webkit.gyp
index f759ba3..53e7602 100644
--- a/webkit/webkit.gyp
+++ b/webkit/webkit.gyp
@@ -4500,9 +4500,6 @@
         'glue/webframe_impl.h',
         'glue/webframeloaderclient_impl.cc',
         'glue/webframeloaderclient_impl.h',
-        'glue/webhistoryitem.h',
-        'glue/webhistoryitem_impl.cc',
-        'glue/webhistoryitem_impl.h',
         'glue/webkit_glue.cc',
         'glue/webkit_glue.h',
         'glue/webkitclient_impl.cc',