Avoid stale navigation requests without excessive page id knowledge in the renderer process.

content/renderer/render_view_impl.h

Index: content/renderer/render_view_impl.h
diff --git a/content/renderer/render_view_impl.h b/content/renderer/render_view_impl.h
index c6eb3642eb2bb41115370f764a7597f682998213..fd38512b88ebcdd3a20ef0856ac03f3ea1e9003c 100644
--- a/content/renderer/render_view_impl.h
+++ b/content/renderer/render_view_impl.h
@@ -184,8 +184,6 @@ class CONTENT_EXPORT RenderViewImpl
   // May return NULL when the view is closing.
   blink::WebView* webview() const;
 
-  int history_list_offset() const { return history_list_offset_; }
-
   const WebPreferences& webkit_preferences() const {
     return webkit_preferences_;
   }
@@ -551,8 +549,6 @@ class CONTENT_EXPORT RenderViewImpl
                            DidFailProvisionalLoadWithErrorForError);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest,
                            DidFailProvisionalLoadWithErrorForCancellation);
-  FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest,
-                           DontIgnoreBackAfterNavEntryLimit);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, ImeComposition);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, InsertCharacters);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, JSBlockSentAfterPageLoad);
@@ -574,7 +570,7 @@ class CONTENT_EXPORT RenderViewImpl
 #if defined(OS_MACOSX)
   FRIEND_TEST_ALL_PREFIXES(RenderViewTest, MacTestCmdUp);
 #endif
-  FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, SetHistoryLengthAndPrune);
+  FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, SetHistoryLengthAndOffset);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, ZoomLimit);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, NavigateFrame);
   FRIEND_TEST_ALL_PREFIXES(RenderViewImplTest, BasicRenderFrame);
@@ -685,7 +681,7 @@ class CONTENT_EXPORT RenderViewImpl
   void OnSetActive(bool active);
   void OnSetBackgroundOpaque(bool opaque);
   void OnExitFullscreen();
-  void OnSetHistoryLengthAndPrune(int history_length, int32 minimum_page_id);
+  void OnSetHistoryOffsetAndLength(int history_offset, int history_length);
   void OnSetInitialFocus(bool reverse);
   void OnSetPageEncoding(const std::string& encoding_name);
   void OnSetRendererPrefs(const RendererPreferences& renderer_prefs);
@@ -732,12 +728,6 @@ class CONTENT_EXPORT RenderViewImpl
   // Returns NULL if there is no such WebPlugin.
   blink::WebPlugin* GetWebPluginForFind();
 
-  // Returns true if the |params| navigation is to an entry that has been
-  // cropped due to a recent navigation the browser did not know about.
-  bool IsBackForwardToStaleEntry(const PageState& state,
-                                 int pending_history_list_offset,
-                                 int32 page_id,
-                                 bool is_reload);
 
   // If we initiated a navigation, this function will populate |document_state|
   // with the navigation information saved in OnNavigate().
@@ -892,11 +882,7 @@ class CONTENT_EXPORT RenderViewImpl
   // The offset of the current item in the history list.
   int history_list_offset_;
 
-  // The RenderView's current impression of the history length.  This includes
-  // any items that have committed in this process, but because of cross-process
-  // navigations, the history may have some entries that were committed in other
-  // processes.  We won't know about them until the next navigation in this
-  // process.

[Charlie Reis, 2014/12/03 23:48:07]

Any reason to delete this?  Sounds like it's still true, and potentially helpful
for reasoning about how fresh the data is.

[Avi (use Gerrit), 2014/12/04 21:15:16]

Done.

+  // The RenderView's current impression of the history length.
   int history_list_length_;
 
   // Counter to track how many frames have sent start notifications but not stop
@@ -904,12 +890,6 @@ class CONTENT_EXPORT RenderViewImpl
   // are gone.
   int frames_in_progress_;
 
-  // The list of page IDs for each history item this RenderView knows about.
-  // Some entries may be -1 if they were rendered by other processes or were
-  // restored from a previous session.  This lets us detect attempts to
-  // navigate to stale entries that have been cropped from our history.
-  std::vector<int32> history_page_ids_;

[Charlie Reis, 2014/12/03 23:48:07]

Woo hoo!

[Avi (use Gerrit), 2014/12/04 21:15:16]

Acknowledged.

-
   // UI state ------------------------------------------------------------------
 
   // The state of our target_url transmissions. When we receive a request to