chrome/browser/thumbnails/thumbnail_tab_helper.h

   1 // Copyright (c) 2012 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_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
   6 #define CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "chrome/browser/thumbnails/thumbnailing_context.h"
  10 #include "content/public/browser/notification_observer.h"
  11 #include "content/public/browser/notification_registrar.h"
  12 #include "content/public/browser/readback_types.h"
  13 #include "content/public/browser/web_contents_observer.h"
  14 #include "content/public/browser/web_contents_user_data.h"
  15
  16 namespace content {
  17 class RenderViewHost;
  18 class RenderWidgetHost;
  19 }
  20
  21 class ThumbnailTabHelper
  22     : public content::NotificationObserver,
  23       public content::WebContentsObserver,
  24       public content::WebContentsUserData<ThumbnailTabHelper> {
  25  public:
  26   ~ThumbnailTabHelper() override;
  27
  28   // Enables or disables the function of taking thumbnails.
  29   // A disabled ThumbnailTabHelper generates no thumbnails although it still
  30   // continues to receive the notifications from the web contents.
  31   void set_enabled(bool enabled) { enabled_ = enabled; }
  32
  33  private:
  34   explicit ThumbnailTabHelper(content::WebContents* contents);
  35   friend class content::WebContentsUserData<ThumbnailTabHelper>;
  36
  37   // content::NotificationObserver overrides.
  38   void Observe(int type,
  39                const content::NotificationSource& source,
  40                const content::NotificationDetails& details) override;
  41
  42   // content::WebContentsObserver overrides.
  43   void RenderViewDeleted(content::RenderViewHost* render_view_host) override;
  44   void DidStartLoading() override;
  45   void NavigationStopped() override;
  46
  47   // Update the thumbnail of the given tab contents if necessary.
  48   void UpdateThumbnailIfNecessary(content::WebContents* web_contents);
  49
  50   // Called when a render view host was created for a WebContents.
  51   void RenderViewHostCreated(content::RenderViewHost* renderer);
  52
  53   // Indicates that the given widget has changed is visibility.
  54   void WidgetHidden(content::RenderWidgetHost* widget);
  55
  56   bool enabled_;
  57
  58   content::NotificationRegistrar registrar_;
  59
  60   bool load_interrupted_;
  61
  62   DISALLOW_COPY_AND_ASSIGN(ThumbnailTabHelper);
  63 };
  64
  65 #endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_