This adds periodic OOM score adjustment, based on the last access time

chrome/browser/tab_contents/tab_contents.cc

 // Copyright (c) 2010 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/tab_contents/tab_contents.h"
 
 #if defined(OS_CHROMEOS)
 // For GdkScreen
 #include <gdk/gdk.h>
 #endif  // defined(OS_CHROMEOS)
@@ skipping 771 matching lines @@
   controller_.SetActive(true);
   RenderWidgetHostView* rwhv = GetRenderWidgetHostView();
   if (rwhv) {
     rwhv->DidBecomeSelected();
 #if defined(OS_MACOSX)
     rwhv->SetActive(true);
 #endif
   }
 
   WebCacheManager::GetInstance()->ObserveActivity(GetRenderProcessHost()->id());
+  last_selected_time_ = base::TimeTicks::Now();
 }
 
 void TabContents::WasHidden() {
   if (!capturing_contents()) {
     // |render_view_host()| can be NULL if the user middle clicks a link to open
     // a tab in then background, then closes the tab before selecting it.  This
     // is because closing the tab calls TabContents::Destroy(), which removes
     // the |render_view_host()|; then when we actually destroy the window,
     // OnWindowPosChanged() notices and calls HideContents() (which calls us).
     RenderWidgetHostView* rwhv = GetRenderWidgetHostView();
@@ skipping 2443 matching lines @@
   AddInfoBar(new SavePasswordInfoBarDelegate(this, form_to_save));
 }
 
 Profile* TabContents::GetProfileForPasswordManager() {
   return profile();
 }
 
 bool TabContents::DidLastPageLoadEncounterSSLErrors() {
   return controller().ssl_manager()->ProcessedSSLErrorFromRequest();
 }