chrome/browser/ui/tabs/tab_discard_state.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_UI_TABS_TAB_DISCARD_STATE_H_
   6 #define CHROME_BROWSER_UI_TABS_TAB_DISCARD_STATE_H_
   7
   8 #include "base/supports_user_data.h"
   9
  10 namespace content {
  11 class WebContents;
  12 }
  13
  14 // Manages the information about the discarding state of a tab. This data is
  15 // stored in WebContents.
  16 class TabDiscardState : public base::SupportsUserData::Data {
  17  public:
  18   // Returns the TabDiscardState associated with |web_contents|. It will create
  19   // one if none exists.
  20   static TabDiscardState* Get(content::WebContents* web_contents);
  21
  22   // Sets the TabDiscardState of a |web_contents|. The object referenced by
  23   // |state| is now owned by |web_contents|
  24   static void Set(content::WebContents* web_contents, TabDiscardState* state);
  25
  26   // Returns true if |web_contents| has been discarded to save memory.
  27   static bool IsDiscarded(content::WebContents* web_contents);
  28
  29   // Sets/clears the discard state of |web_contents|.
  30   static void SetDiscardState(content::WebContents* web_contents, bool state);
  31
  32   // Returns the number of times |web_contents| has been discarded.
  33   static int DiscardCount(content::WebContents* web_contents);
  34
  35   // Increments the number of times |web_contents| has been discarded.
  36   static void IncrementDiscardCount(content::WebContents* web_contents);
  37
  38   // Copies the discard state from |old_contents| to |new_contents|.
  39   static void CopyState(content::WebContents* old_contents,
  40                         content::WebContents* new_contents);
  41
  42   TabDiscardState() : is_discarded_(false), discard_count_(0) {}
  43
  44  private:
  45   // Is the tab currently discarded?
  46   bool is_discarded_;
  47
  48   // Number of times the tab has been discarded.
  49   int discard_count_;
  50 };
  51
  52 #endif  // CHROME_BROWSER_UI_TABS_TAB_DISCARD_STATE_H_