Migrate HostZoomMap to live in StoragePartition.

chrome/browser/ui/zoom/zoom_level_prefs_store_impl.h

+// Copyright (c) 2014 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_UI_ZOOM_ZOOM_LEVEL_PREFS_STORE_IMPL_H_
+#define CHROME_BROWSER_UI_ZOOM_ZOOM_LEVEL_PREFS_STORE_IMPL_H_
+
+#include "content/public/browser/zoom_level_prefs_store.h"
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/prefs/json_pref_store.h"
+#include "base/prefs/pref_store.h"
+#include "chrome/browser/prefs/pref_service_syncable.h"
+#include "content/public/browser/host_zoom_map.h"
+
+namespace chrome {
+
+// A class to implement ZoomLevelPrefsStore. It also implements
+// PrefStore::Observer so that it can track changes to the prefs.
+// Finally, the prefs are also updated in response to zoom events
+// from HostZoomMap.
+class ZoomLevelPrefsStoreImpl : public PrefStore::Observer,
+                                public content::ZoomLevelPrefsStore {
+ public:
+  ZoomLevelPrefsStoreImpl();
+  virtual ~ZoomLevelPrefsStoreImpl();
+  void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
+
+  // Implement ZoomLevelPrefsStore.
+  virtual void InitPrefsAndCopyToHostZoomMap(
+      const base::FilePath& file_path,
+      content::HostZoomMap* host_zoom_map) OVERRIDE;
+  virtual PrefService* GetPrefs() OVERRIDE;
+
+  // Implement PrefObserver.
+  virtual void OnPrefValueChanged(const std::string& key) OVERRIDE;
+  virtual void OnInitializationCompleted(bool succeeded) OVERRIDE;
+
+ private:
+
+  scoped_refptr<JsonPrefStore> zoom_level_prefs_;
+  scoped_ptr<PrefServiceSyncable> pref_service_;
+  scoped_ptr<content::HostZoomMap::Subscription> zoom_subscription_;
+  content::HostZoomMap* host_zoom_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(ZoomLevelPrefsStoreImpl);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_ZOOM_ZOOM_LEVEL_PREFS_STORE_IMPL_H_