[Sync] Introduce SyncedSessionWindow type.

components/sync_sessions/sync_sessions_metrics_unittest.cc

 // Copyright 2016 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 "components/sync_sessions/sync_sessions_metrics.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "base/memory/ptr_util.h"
@@ skipping 52 matching lines @@
   // calls in here are safe because the session/window objects are going to
   // delete all their children when their destructors are invoked.
   void PushTab(size_t tabIndex, int windowIndex, Time timestamp) {
     // First add sessions/windows as necessary.
     while (tabIndex >= sessions_.size()) {
       sessions_.push_back(base::MakeUnique<SyncedSession>());
     }
     if (sessions_[tabIndex]->windows.find(windowIndex) ==
         sessions_[tabIndex]->windows.end()) {
       sessions_[tabIndex]->windows[windowIndex] =
-          base::MakeUnique<SessionWindow>();
+          base::MakeUnique<SyncedSessionWindow>();
     }
 
     sessions_[tabIndex]->modified_time =
         std::max(sessions_[tabIndex]->modified_time, timestamp);
-    sessions_[tabIndex]->windows[windowIndex]->timestamp = std::max(
-        sessions_[tabIndex]->windows[windowIndex]->timestamp, timestamp);
-    sessions_[tabIndex]->windows[windowIndex]->tabs.push_back(
+    sessions_[tabIndex]->windows[windowIndex]->wrapped_window.timestamp =
+        std::max(
+            sessions_[tabIndex]->windows[windowIndex]->wrapped_window.timestamp,
+            timestamp);
+    sessions_[tabIndex]->windows[windowIndex]->wrapped_window.tabs.push_back(
         base::MakeUnique<SessionTab>());
-    sessions_[tabIndex]->windows[windowIndex]->tabs.back()->timestamp =
-        timestamp;
+    sessions_[tabIndex]
+        ->windows[windowIndex]
+        ->wrapped_window.tabs.back()
+        ->timestamp = timestamp;
   }
 
   // Removes the last tab at the given indexes. The idexes provided should be
   // valid for existing data, this method does not check their validity. Windows
   // are not cleaned up/removed if they're left with 0 tabs.
   void PopTab(size_t tabIndex, int windowIndex, Time timestamp) {
     sessions_[tabIndex]->modified_time =
         std::max(sessions_[tabIndex]->modified_time, timestamp);
-    sessions_[tabIndex]->windows[windowIndex]->timestamp = std::max(
-        sessions_[tabIndex]->windows[windowIndex]->timestamp, timestamp);
-    sessions_[tabIndex]->windows[windowIndex]->tabs.pop_back();
+    sessions_[tabIndex]->windows[windowIndex]->wrapped_window.timestamp =
+        std::max(
+            sessions_[tabIndex]->windows[windowIndex]->wrapped_window.timestamp,
+            timestamp);
+    sessions_[tabIndex]->windows[windowIndex]->wrapped_window.tabs.pop_back();
   }
 
   // Runs MaxTabTimestamp on the current sessions data.
   Time MaxTabTimestamp() {
     std::vector<const SyncedSession*> typed_sessions;
     for (auto& session : sessions_) {
       typed_sessions.push_back(session.get());
     }
     return SyncSessionsMetrics::MaxTabTimestamp(typed_sessions);
   }
@@ skipping 90 matching lines @@
 
 TEST_F(SyncSessionsMetricsTest, EmitNormalCase) {
   base::HistogramTester histogram_tester;
   PushTab(0, 0, Time::Now() - TimeDelta::FromHours(1));
   SyncSessionsMetrics::RecordYoungestForeignTabAgeOnNTP(
       get_sessions_sync_manager());
   histogram_tester.ExpectTotalCount("Sync.YoungestForeignTabAgeOnNTP", 1);
 }
 
 }  // namespace sync_sessions