Reland of Add Resume logic of Purge+Suspend to TabManager.

chrome/browser/memory/tab_manager_web_contents_data.cc

 // Copyright 2015 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/memory/tab_manager_web_contents_data.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/time/tick_clock.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/engagement/site_engagement_service.h"
@@ skipping 186 matching lines @@
   g_browser_process->GetTabManager()->OnAutoDiscardableStateChange(
       web_contents(), state);
 }
 
 bool TabManager::WebContentsData::IsAutoDiscardable() {
   return tab_data_.is_auto_discardable;
 }
 
 void TabManager::WebContentsData::SetPurgeAndSuspendState(
     PurgeAndSuspendState state) {
-  last_purge_and_suspend_modified_time_ = TimeTicks::Now();
+  last_purge_and_suspend_modified_time_ = NowTicks();
   purge_and_suspend_state_ = state;
 }
 
 base::TimeTicks TabManager::WebContentsData::LastPurgeAndSuspendModifiedTime()
     const {
   return last_purge_and_suspend_modified_time_;
 }
 
+void TabManager::WebContentsData::SetLastPurgeAndSuspendModifiedTimeForTesting(
+    base::TimeTicks timestamp) {
+  last_purge_and_suspend_modified_time_ = timestamp;
+}
+
 TabManager::PurgeAndSuspendState
 TabManager::WebContentsData::GetPurgeAndSuspendState() const {
   return purge_and_suspend_state_;
 }
 
 }  // namespace memory