Move ownership of source SiteInstance to the FrameNavigationEntry.

content/browser/frame_host/frame_navigation_entry.h

 // Copyright 2015 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_FRAME_NAVIGATION_ENTRY_H_
 #define CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 29 matching lines @@
                        int64_t post_id);
 
   // Creates a copy of this FrameNavigationEntry that can be modified
   // independently from the original.
   FrameNavigationEntry* Clone() const;
 
   // Updates all the members of this entry.
   void UpdateEntry(const std::string& frame_unique_name,
                    int64_t item_sequence_number,
                    int64_t document_sequence_number,
+                   SiteInstanceImpl* source_site_instance,

[dcheng, 2016/05/04 17:01:45]

Random aside: it would be kind of nice if ownership taking parameters were
passed by scoped_refptr. That would make the downcasting quite a bit uglier
though.

[nasko, 2016/05/05 17:51:32]

In this case we won't need to downcast, would we? It is already the Impl type.

                    SiteInstanceImpl* site_instance,

[Charlie Reis, 2016/05/04 23:03:01]

nit: Please list source_site_instance after site_instance, since site_instance
is more important and always present.

[nasko, 2016/05/05 17:51:32]

Done.

                    const GURL& url,
                    const Referrer& referrer,
                    const PageState& page_state,
                    const std::string& method,
                    int64_t post_id);
 
   // The unique name of the frame this entry is for.  This is a stable name for
   // the frame based on its position in the tree and relation to other named
   // frames, which does not change after cross-process navigations or restores.
   // Only the main frame can have an empty name.
@@ skipping 18 matching lines @@
 
   // The SiteInstance responsible for rendering this frame.  All frames sharing
   // a SiteInstance must live in the same process.  This is a refcounted pointer
   // that keeps the SiteInstance (not necessarily the process) alive as long as
   // this object remains in the session history.
   void set_site_instance(scoped_refptr<SiteInstanceImpl> site_instance) {
     site_instance_ = std::move(site_instance);
   }
   SiteInstanceImpl* site_instance() const { return site_instance_.get(); }
 
+  // The |source_site_instance| is used to identify the SiteInstance of the
+  // frame that initiated the navigation.

[Charlie Reis, 2016/05/04 23:03:01]

nit: Let's mention that it is cleared after commit and only present on
renderer-initiated navigations, so people don't assume they can use it
otherwise.

[nasko, 2016/05/05 17:51:32]

Done.

+  void set_source_site_instance(SiteInstanceImpl* source_site_instance) {
+    source_site_instance_ = source_site_instance;
+  }
+  SiteInstanceImpl* source_site_instance() const {
+    return source_site_instance_.get();
+  }
+
   // The actual URL loaded in the frame.  This is in contrast to the virtual
   // URL, which is shown to the user.
   void set_url(const GURL& url) { url_ = url; }
   const GURL& url() const { return url_; }
 
   // The referring URL.  Can be empty.
   void set_referrer(const Referrer& referrer) { referrer_ = referrer; }
   const Referrer& referrer() const { return referrer_; }
 
   void set_page_state(const PageState& page_state) { page_state_ = page_state; }
@@ skipping 23 matching lines @@
   int64_t item_sequence_number_;
   int64_t document_sequence_number_;
   scoped_refptr<SiteInstanceImpl> site_instance_;
   GURL url_;
   Referrer referrer_;
   // TODO(creis): Change this to FrameState.
   PageState page_state_;
   std::string method_;
   int64_t post_id_;
 
+  // This member is cleared at commit time and not persisted.

[Charlie Reis, 2016/05/04 23:03:01]

nit: and is not

[nasko, 2016/05/05 17:51:32]

Done.

+  scoped_refptr<SiteInstanceImpl> source_site_instance_;
+
   DISALLOW_COPY_AND_ASSIGN(FrameNavigationEntry);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_