Add Resume logic of Purge+Suspend to TabManager.

chrome/browser/memory/tab_manager.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_MEMORY_TAB_MANAGER_H_
 #define CHROME_BROWSER_MEMORY_TAB_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 141 matching lines @@
 
   // Returns true if |first| is considered less desirable to be killed than
   // |second|.
   static bool CompareTabStats(const TabStats& first, const TabStats& second);
 
   // Returns a unique ID for a WebContents. Do not cast back to a pointer, as
   // the WebContents could be deleted if the user closed the tab.
   static int64_t IdFromWebContents(content::WebContents* web_contents);
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(TabManagerTest,
+                           ActivateTabResetPurgeAndSuspendState);
+  FRIEND_TEST_ALL_PREFIXES(TabManagerTest, NextPurgeAndSuspendState);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, AutoDiscardable);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, CanOnlyDiscardOnce);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, ChildProcessNotifications);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, Comparator);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, DiscardedTabKeepsLastActiveTime);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, DiscardWebContentsAt);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, InvalidOrEmptyURL);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, IsInternalPage);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, OomPressureListener);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, ProtectPDFPages);
@@ skipping 91 matching lines @@
   //   purge-and-suspend modified time), and
   // - kSuspendedRendererLengthOfResumption time passes since the tab was
   //   resumed.
   // SUSPENDED, RESUMED, RUNNING => RUNNING
   // - When ActiveTabChaged, the newly activated tab's state will be RUNNING.
   enum PurgeAndSuspendState {
     RUNNING,
     RESUMED,
     SUSPENDED,
   };
+  // Returns WebContents whose contents id matches the given tab_contents_id.
+  content::WebContents* GetWebContentsById(int64_t tab_contents_id);
+
+  // Returns the next state of the purge and suspend.
+  PurgeAndSuspendState GetNextPurgeAndSuspendState(
+      content::WebContents* content,
+      base::TimeTicks current_time,
+      const base::TimeDelta& time_to_first_suspension) const;
 
   // 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).
   content::WebContents* DiscardWebContentsAt(int index, TabStripModel* model);
 
   // Called by the memory pressure listener when the memory pressure rises.
@@ skipping 123 matching lines @@
 
   // Weak pointer factory used for posting delayed tasks to task_runner_.
   base::WeakPtrFactory<TabManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TabManager);
 };
 
 }  // namespace memory
 
 #endif  // CHROME_BROWSER_MEMORY_TAB_MANAGER_H_