Experimental 'purging and suspending' backgrounded tabs behind the flag

chrome/browser/memory/tab_manager.h

Index: chrome/browser/memory/tab_manager.h
diff --git a/chrome/browser/memory/tab_manager.h b/chrome/browser/memory/tab_manager.h
index d1f3741e501f612887619ab61b3a4e8c1d6a1197..2f82d0c81cdb1e71a4cab90b6a7cd94eb5726a3e 100644
--- a/chrome/browser/memory/tab_manager.h
+++ b/chrome/browser/memory/tab_manager.h
@@ -195,6 +195,9 @@ class TabManager : public TabStripModelObserver {
   // that need to be run periodically (see comment in implementation).
   void UpdateTimerCallback();
 
+  // Purges and suspends renderers in backgrounded tabs.
+  void PurgeAndSuspendBackgroundedTabs();
+
   // Does the actual discard by destroying the WebContents in |model| at |index|
   // and replacing it by an empty one. Returns the new WebContents or NULL if
   // the operation fails (return value used only in testing).