chrome/browser/ui/cocoa/handoff_active_url_observer.h

   1 // Copyright 2014 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_COCOA_HANDOFF_ACTIVE_URL_OBSERVER_H_
   6 #define CHROME_BROWSER_UI_COCOA_HANDOFF_ACTIVE_URL_OBSERVER_H_
   7
   8 #include "chrome/browser/ui/browser_list_observer.h"
   9 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
  10 #include "content/public/browser/web_contents_observer.h"
  11
  12 namespace content {
  13 class WebContents;
  14 }
  15
  16 class Browser;
  17 class HandoffActiveURLObserverDelegate;
  18 class TabStripModel;
  19
  20 // This class observes changes to the "active URL". This is defined as the
  21 // visible URL of the WebContents of the selected tab of the most recently
  22 // focused browser window.
  23 class HandoffActiveURLObserver : public chrome::BrowserListObserver,
  24                                  public TabStripModelObserver,
  25                                  public content::WebContentsObserver {
  26  public:
  27   explicit HandoffActiveURLObserver(HandoffActiveURLObserverDelegate* delegate);
  28   ~HandoffActiveURLObserver() override;
  29
  30  private:
  31   // chrome::BrowserListObserver
  32   void OnBrowserSetLastActive(Browser* browser) override;
  33   void OnBrowserRemoved(Browser* browser) override;
  34
  35   // TabStripModelObserver
  36   void ActiveTabChanged(content::WebContents* old_contents,
  37                         content::WebContents* new_contents,
  38                         int index,
  39                         int reason) override;
  40   void TabStripModelDeleted() override;
  41
  42   // content::WebContentsObserver
  43   void DidNavigateMainFrame(
  44       const content::LoadCommittedDetails& details,
  45       const content::FrameNavigateParams& params) override;
  46   void WebContentsDestroyed() override;
  47
  48   // This method ensures that the instance is registered as an observer of the
  49   // correct TabStripModel and WebContents for |active_browser_|.
  50   void UpdateObservations();
  51
  52   // Makes this object start observing the TabStripModel, if it is not already
  53   // doing so. This method is idempotent.
  54   void StartObservingTabStripModel(TabStripModel* tab_strip_model);
  55
  56   // Makes this object stop observing the TabStripModel.
  57   void StopObservingTabStripModel();
  58
  59   // Makes this object start observing the WebContents, if it is not already
  60   // doing so. This method is idempotent.
  61   void StartObservingWebContents(content::WebContents* web_contents);
  62
  63   // Makes this object stop observing the WebContents.
  64   void StopObservingWebContents();
  65
  66   // Returns the active WebContents. May return nullptr.
  67   content::WebContents* GetActiveWebContents();
  68
  69   // Instances of this class should be owned by their |delegate_|.
  70   HandoffActiveURLObserverDelegate* delegate_;
  71
  72   // When this pointer is not nullptr, this object is registered as an observer
  73   // of the TabStripModel.
  74   TabStripModel* active_tab_strip_model_;
  75
  76   // This pointer is always up to date, and points to the most recently
  77   // activated browser, or nullptr if no browsers exist.
  78   Browser* active_browser_;
  79
  80   DISALLOW_COPY_AND_ASSIGN(HandoffActiveURLObserver);
  81 };
  82
  83 #endif  // CHROME_BROWSER_UI_COCOA_HANDOFF_ACTIVE_URL_OBSERVER_H_