[Sync] Fix Session's handling of windows.

chrome/browser/sync/glue/synced_session.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/sync/glue/synced_session.h"
 
 #include "base/stl_util.h"
 #include "chrome/browser/sessions/session_types.h"
+#include "chrome/common/url_constants.h"
 
 namespace browser_sync {
 
 SyncedSession::SyncedSession() : session_tag("invalid"),
                                  device_type(TYPE_UNSET) {
 }
 
 SyncedSession::~SyncedSession() {
-  STLDeleteElements(&windows);
+  STLDeleteContainerPairSecondPointers(windows.begin(), windows.end());
+}
+
+// Note: if you modify this, make sure you modify IsValidTab in
+// SessionModelAssociator.
+bool IsValidSessionTab(const SessionTab& tab) {
+  if (tab.navigations.empty())
+    return false;
+  int selected_index = tab.current_navigation_index;
+  selected_index = std::max(
+      0,
+      std::min(selected_index,
+          static_cast<int>(tab.navigations.size() - 1)));
+  if (selected_index == 0 &&
+      tab.navigations.size() == 1 &&
+      tab.navigations.at(selected_index).virtual_url().GetOrigin() ==
+          GURL(chrome::kChromeUINewTabURL)) {
+    // This is a new tab with no further history, skip.
+    return false;
+  }
+  return true;
+}
+
+bool SessionWindowHasNoTabsToSync(const SessionWindow& window) {
+  int num_populated = 0;
+  for (std::vector<SessionTab*>::const_iterator i = window.tabs.begin();
+      i != window.tabs.end(); ++i) {
+    const SessionTab* tab = *i;
+    if (IsValidSessionTab(*tab))
+      num_populated++;
+  }
+  return (num_populated == 0);
 }
 
 }  // namespace browser_sync