Send a subtree of same-process PageStates for back/forward child frames.

content/browser/frame_host/navigation_entry_impl.h

 // Copyright 2013 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 CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_IMPL_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 169 matching lines @@
       const GURL& dest_url,
       const Referrer& dest_referrer,
       FrameMsg_Navigate_Type::Value navigation_type,
       LoFiState lofi_state,
       const base::TimeTicks& navigation_start) const;
   StartNavigationParams ConstructStartNavigationParams() const;
   RequestNavigationParams ConstructRequestNavigationParams(
       const FrameNavigationEntry& frame_entry,
       bool is_same_document_history_load,
       bool is_history_navigation_in_new_child,
-      const std::map<std::string, bool>& subframe_unique_names,
+      const std::map<std::string, PageState>& subtree_page_states,
       bool has_committed_real_load,
       bool intended_as_new_entry,
       int pending_offset_to_send,
       int current_offset_to_send,
       int current_length_to_send) const;
 
   // Once a navigation entry is committed, we should no longer track several
   // pieces of non-persisted state, as documented on the members below.
   // |frame_entry| is the FrameNavigationEntry for the frame that committed
   // the navigation. It can be null.
@@ skipping 24 matching lines @@
       const Referrer& referrer,
       const std::vector<GURL>& redirect_chain,
       const PageState& page_state,
       const std::string& method,
       int64_t post_id);
 
   // Returns the FrameNavigationEntry corresponding to |frame_tree_node|, if
   // there is one in this NavigationEntry.
   FrameNavigationEntry* GetFrameEntry(FrameTreeNode* frame_tree_node) const;
 
-  // Returns a map of frame unique names to |is_about_blank| for immediate
-  // children of the TreeNode associated with |frame_tree_node|.  The renderer
-  // process will use this list of names to know whether to ask the browser
-  // process for a history item when new subframes are created during a
-  // back/forward navigation.  (|is_about_blank| can be used to skip the request
-  // if the frame's default URL is about:blank and the history item would be a
-  // no-op.  See https://crbug.com/657896.)
-  // TODO(creis): Send a data structure that also contains all corresponding
-  // same-process PageStates for the whole subtree, so that the renderer process
-  // only needs to ask the browser process to handle the cross-process cases.
-  // See https://crbug.com/639842.
-  std::map<std::string, bool> GetSubframeUniqueNames(
+  // Returns a map of frame unique names to PageStates for the subtree of
+  // FrameNavigationEntries underneath |frame_tree_node|.  This map contains
+  // names for every frame in the subtree, and valid PageStates for those frames
+  // that should load in the same SiteInstance.  Cross-SiteInstance frames are
+  // given empty PageStates here.
+  //
+  // The renderer process uses this list of names to know whether there is a
+  // history item to use when new subframes are created during a back/forward
+  // navigation.  If the corresponding PageState is valid, the renderer can
+  // directly load it without asking the browser.  If the PageState is empty,
+  // it corresponds to an out-of-process iframe and the renderer asks the
+  // browser process to navigate that frame instead.
+  //
+  // TODO(creis): When the SiteInstance is missing, such as after restore, this
+  // causes the browser to send PageStates to the renderer even when they should
+  // be destined for an OOPIF.  Persist SiteInstance relationships to prevent
+  // this.  See https://crbug.com/14987.
+  std::map<std::string, PageState> GetSubtreePageStates(
       FrameTreeNode* frame_tree_node) const;
 
   // Removes any subframe FrameNavigationEntries that match the unique name of
   // |frame_tree_node|, and all of their children. There should be at most one,
   // since collisions are avoided but leave old FrameNavigationEntries in the
   // tree after their frame has been detached.
   void ClearStaleFrameEntriesForNewFrame(FrameTreeNode* frame_tree_node);
 
   void set_unique_id(int unique_id) {
     unique_id_ = unique_id;
@@ skipping 285 matching lines @@
   // persisted, unless specific data is taken out/put back in at save/restore
   // time (see TabNavigation for an example of this).
   std::map<std::string, base::string16> extra_data_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationEntryImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_IMPL_H_