Makes session restore work correctly with instant.

BUG=58956
TEST=see bug

Review URL: http://codereview.chromium.org/3783005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@62738 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 8 insertions, 0 deletions

diff --git a/chrome/browser/sessions/session_id.h b/chrome/browser/sessions/session_id.h
index 1731d59..3036386 100644
--- a/chrome/browser/sessions/session_id.h
+++ b/chrome/browser/sessions/session_id.h
@@ -8,6 +8,7 @@
 
 #include "base/basictypes.h"
 
+class NavigationController;
 class SessionService;
 
 // Uniquely identifies a tab or window for the duration of a session.
@@ -22,10 +23,14 @@ class SessionID {
   id_type id() const { return id_; }
 
  private:
+  friend class NavigationController;
   friend class SessionService;
 
   explicit SessionID(id_type id) : id_(id) {}
 
+  // Resets the ID to 0.
+  void clear() { id_ = 0; }
+
   // Resets the id. This is used when restoring a session
   void set_id(id_type id) { id_ = id; }
 
diff --git a/chrome/browser/sessions/session_service.cc b/chrome/browser/sessions/session_service.cc
index a430d56..b0ba070 100644
--- a/chrome/browser/sessions/session_service.cc
+++ b/chrome/browser/sessions/session_service.cc
@@ -215,6 +215,9 @@ void SessionService::SetPinnedState(const SessionID& window_id,
 void SessionService::TabClosed(const SessionID& window_id,
                                const SessionID& tab_id,
                                bool closed_by_user_gesture) {
+  if (!tab_id.id())
+    return;  // Hapens when the tab is replaced.
+
   if (!ShouldTrackChangesToWindow(window_id))
     return;