content/browser/host_zoom_level_context.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 CONTENT_BROWSER_HOST_ZOOM_LEVEL_CONTEXT_H_
   6 #define CONTENT_BROWSER_HOST_ZOOM_LEVEL_CONTEXT_H_
   7
   8 #include "base/macros.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "content/browser/host_zoom_map_impl.h"
  12 #include "content/public/browser/zoom_level_delegate.h"
  13
  14 class PrefService;
  15
  16 namespace content {
  17 struct HostZoomLevelContextDeleter;
  18
  19 // This class manages a HostZoomMap and associates it with a ZoomLevelDelegate,
  20 // if one is provided. It also serves to keep the zoom level machinery details
  21 // separate from the owning StoragePartitionImpl.
  22 class HostZoomLevelContext
  23     : public base::RefCountedThreadSafe<HostZoomLevelContext,
  24                                         HostZoomLevelContextDeleter> {
  25  public:
  26   explicit HostZoomLevelContext(
  27       scoped_ptr<ZoomLevelDelegate> zoom_level_delegate);
  28
  29   HostZoomMap* GetHostZoomMap() const { return host_zoom_map_impl_.get(); }
  30   ZoomLevelDelegate* GetZoomLevelDelegate() const {
  31     return zoom_level_delegate_.get();
  32   }
  33
  34  protected:
  35   virtual ~HostZoomLevelContext();
  36
  37  private:
  38   friend class base::DeleteHelper<HostZoomLevelContext>;
  39   friend class base::RefCountedThreadSafe<HostZoomLevelContext,
  40                                           HostZoomLevelContextDeleter>;
  41   friend struct HostZoomLevelContextDeleter;
  42
  43   void DeleteOnCorrectThread() const;
  44
  45   scoped_ptr<HostZoomMapImpl> host_zoom_map_impl_;
  46   // Release the delegate before the HostZoomMap, in case it is carrying
  47   // any HostZoomMap::Subscription pointers.
  48   scoped_ptr<ZoomLevelDelegate> zoom_level_delegate_;
  49
  50   DISALLOW_COPY_AND_ASSIGN(HostZoomLevelContext);
  51 };
  52
  53 struct HostZoomLevelContextDeleter {
  54   static void Destruct(const HostZoomLevelContext* context) {
  55     context->DeleteOnCorrectThread();
  56   }
  57 };
  58
  59 }  // namespace content
  60
  61 #endif  // CONTENT_BROWSER_HOST_ZOOM_LEVEL_CONTEXT_H_