Migrate HostZoomMap to live in StoragePartition.

content/public/browser/zoom_level_prefs_store.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 CONTENT_PUBLIC_BROWSER_ZOOM_LEVEL_PREFS_STORE_H_
+#define CONTENT_PUBLIC_BROWSER_ZOOM_LEVEL_PREFS_STORE_H_
+
+class PrefService;
+
+namespace base {
+class FilePath;
+}  // namespace base
+
+namespace content {
+
+class HostZoomMap;
+
+// An interface to manage a prefs store for (1) default zoom level, and
+// (2) per-host zoom levels. It can be used to load the latter into a
+// HostZoomMap.
+class ZoomLevelPrefsStore {
+ public:
+  virtual void InitPrefsAndCopyToHostZoomMap(const base::FilePath& file_path,
+                                             HostZoomMap* host_zoom_map) = 0;
+  virtual ~ZoomLevelPrefsStore() {}
+
+  // Expose for tests.
+  virtual PrefService* GetPrefs() = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_ZOOM_LEVEL_PREFS_STORE_H_