Reland v5 of Sessions Refactor

components/sync/protocol/session_specifics.proto

 // Copyright (c) 2012 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.
 //
 // Sync protocol datatype extension for sessions.
 
 // Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
 // any fields in this file.
 
 syntax = "proto2";
@@ skipping 36 matching lines @@
     TYPE_CUSTOM_TAB = 3;  // A custom tab within an app. Not restored
                           // automatically on sync startup.
   }
   optional BrowserType browser_type = 3 [default = TYPE_TABBED];
   // The tabs that compose a window (correspond to tab id's).
   repeated int32 tab = 4;
 }
 
 message SessionTab {
   // Unique (to the owner) id for this tab.
-  optional int32 tab_id = 1;
+  optional int32 tab_id = 1 [default = -1];
   // The unique id for the window this tab belongs to.
   optional int32 window_id = 2;
   // Visual index of the tab within its window. There may be gaps in these
   // values.
   optional int32 tab_visual_index = 3 [default = -1];
   // Identifies the index of the current navigation in navigations. For
   // example, if this is 2 it means the current navigation is navigations[2].
   optional int32 current_navigation_index = 4 [default = -1];
   // True if the tab is pinned.
   optional bool pinned = 5 [default = false];
@@ skipping 88 matching lines @@
   }
   // Whether the Password Manager saw a password field on the page.
   optional PasswordState password_state = 26;
 }
 
 // Navigation information for a single redirection within a single navigation.
 message NavigationRedirect {
   // A URL that redirected while navigating to the virtual_url.
   optional string url = 1;
 }