Move ownership of source SiteInstance to the FrameNavigationEntry.

content/browser/frame_host/navigation_entry_impl.h

Index: content/browser/frame_host/navigation_entry_impl.h
diff --git a/content/browser/frame_host/navigation_entry_impl.h b/content/browser/frame_host/navigation_entry_impl.h
index 2e40e67098d6bce721bb60f9a96acc6fbe1c370c..5221ba7c326d7d473dfb4a5fb4649900373c50c1 100644
--- a/content/browser/frame_host/navigation_entry_impl.h
+++ b/content/browser/frame_host/navigation_entry_impl.h
@@ -177,7 +177,10 @@ class CONTENT_EXPORT NavigationEntryImpl
 
   // Once a navigation entry is committed, we should no longer track several
   // pieces of non-persisted state, as documented on the members below.
-  void ResetForCommit();
+  // |frame_entry| is the FrameNavigationEntry for the frame that committed
+  // the navigation. It can be null if subframe navigation entries are not

[Charlie Reis, 2016/05/05 22:20:00]

I wish it were as simple as "if subframe navigation entries are not in use."  :)

It's also null in all the cases mentioned in https://crbug.com/608402, and
possibly others.  We probably just want to say that it can be null without
saying when, or that it's when we end up with no corresponding
FrameNavigationEntry for a commit.

[nasko, 2016/05/06 00:13:41]

Done.

+  // in use.
+  void ResetForCommit(FrameNavigationEntry* frame_entry);
 
   // Exposes the tree of FrameNavigationEntries that make up this joint session
   // history item.
@@ -194,15 +197,17 @@ class CONTENT_EXPORT NavigationEntryImpl
   // NavigationEntries) is updated with the given parameters.
   // Does nothing if there is no entry already and |url| is about:blank, since
   // that does not count as a real commit.
-  void AddOrUpdateFrameEntry(FrameTreeNode* frame_tree_node,
-                             int64_t item_sequence_number,
-                             int64_t document_sequence_number,
-                             SiteInstanceImpl* site_instance,
-                             const GURL& url,
-                             const Referrer& referrer,
-                             const PageState& page_state,
-                             const std::string& method,
-                             int64_t post_id);
+  void AddOrUpdateFrameEntry(
+      FrameTreeNode* frame_tree_node,
+      int64_t item_sequence_number,
+      int64_t document_sequence_number,
+      SiteInstanceImpl* site_instance,
+      scoped_refptr<SiteInstanceImpl> source_site_instance,
+      const GURL& url,
+      const Referrer& referrer,
+      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.
@@ -224,10 +229,12 @@ class CONTENT_EXPORT NavigationEntryImpl
   }
 
   // The |source_site_instance| is used to identify the SiteInstance of the
-  // frame that initiated the navigation.
-  void set_source_site_instance(SiteInstanceImpl* source_site_instance);
-  SiteInstanceImpl* source_site_instance() const {
-    return source_site_instance_.get();
+  // frame that initiated the navigation. It is set on the
+  // FrameNavigationEntry for the main frame.
+  void set_source_site_instance(
+      scoped_refptr<SiteInstanceImpl> source_site_instance) {
+    root_node()->frame_entry->set_source_site_instance(
+        source_site_instance.get());
   }
 
   // Remember the set of bindings granted to this NavigationEntry at the time
@@ -418,9 +425,6 @@ class CONTENT_EXPORT NavigationEntryImpl
   // This member is not persisted with session restore.
   std::string extra_headers_;
 
-  // This member is cleared in |ResetForCommit| and not persisted.
-  scoped_refptr<SiteInstanceImpl> source_site_instance_;
-
   // Used for specifying base URL for pages loaded via data URLs. Only used and
   // persisted by Android WebView.
   GURL base_url_for_data_url_;