Add setting to isolate zoom changes by default.

chrome/browser/ui/zoom/chrome_zoom_level_prefs.h

 // Copyright 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_CHROME_ZOOM_LEVEL_PREFS_H_
 #define CHROME_BROWSER_UI_ZOOM_CHROME_ZOOM_LEVEL_PREFS_H_
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
-#include "components/prefs/json_pref_store.h"
-#include "components/prefs/pref_change_registrar.h"
+#include "chrome/browser/ui/zoom/chrome_zoom_prefs_helper.h"
 #include "components/prefs/pref_service.h"
-#include "components/prefs/pref_store.h"
+#include "components/zoom/zoom_prefs_delegate.h"
 #include "content/public/browser/host_zoom_map.h"
-#include "content/public/browser/zoom_level_delegate.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace zoom {
 class ZoomEventManager;
 }
 
-// A class to manage per-partition default and per-host zoom levels in Chrome's
-// preference system. It implements an interface between the content/ zoom
-// levels in HostZoomMap and Chrome's preference system. All changes
-// to the per-partition default zoom levels from chrome/ flow through this
+// A class to manage per-partition default and per-host zoom levels as well as
+// the zoom scope pref in Chrome's preference system. It implements an
+// interface to Chrome's preference system for the content/ zoom levels in
+// HostZoomMap and the zoom scope in ZoomController. All changes to the
+// per-partition default zoom levels and scope from chrome/ flow through this
 // class. Any changes to per-host levels are updated when HostZoomMap calls
 // OnZoomLevelChanged.
-class ChromeZoomLevelPrefs : public content::ZoomLevelDelegate {
+class ChromeZoomLevelPrefs : public zoom::ZoomPrefsDelegate {
  public:
   typedef base::CallbackList<void(void)>::Subscription
       DefaultZoomLevelSubscription;
 
-  // Initialize the pref_service and the partition_key via the constructor,
-  // as these concepts won't be available in the content base class
-  // ZoomLevelDelegate, which will define the InitHostZoomMap interface.
+  // Initialize our ChromeZoomPrefsHelper with pref_service and the partition
+  // information via this constructor, as these concepts won't be available in
+  // the content base class ZoomLevelDelegate (which will define the
+  // InitHostZoomMap interface) nor in the components class ZoomPrefsDelegate
+  // (which will define the interface for the zoom scope pref).
   // |pref_service_| must outlive this class.
   ChromeZoomLevelPrefs(
       PrefService* pref_service,
       const base::FilePath& profile_path,
       const base::FilePath& partition_path,
       base::WeakPtr<zoom::ZoomEventManager> zoom_event_manager);
   ~ChromeZoomLevelPrefs() override;
 
   static std::string GetHashForTesting(const base::FilePath& relative_path);
 
   void SetDefaultZoomLevelPref(double level);
   double GetDefaultZoomLevelPref() const;
   std::unique_ptr<DefaultZoomLevelSubscription>
   RegisterDefaultZoomLevelCallback(const base::Closure& callback);
 
+  void SetZoomScopeIsPerOriginPref(bool is_per_origin);
+
   void ExtractPerHostZoomLevels(
       const base::DictionaryValue* host_zoom_dictionary,
       bool sanitize_partition_host_zoom_levels);
 
-  // content::ZoomLevelDelegate
+  // zoom::ZoomPrefsDelegate
   void InitHostZoomMap(content::HostZoomMap* host_zoom_map) override;
 
+  bool GetZoomScopeIsPerOriginPref() const override;
+  std::unique_ptr<DefaultZoomScopeSubscription>
+  RegisterDefaultZoomScopeCallback(const base::Closure& callback) override;
+
  private:
   // This is a callback function that receives notifications from HostZoomMap
   // when per-host zoom levels change. It is used to update the per-host
   // zoom levels (if any) managed by this class (for its associated partition).
   void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
 
-  PrefService* pref_service_;
+  ChromeZoomPrefsHelper partitioned_prefs_;
   base::WeakPtr<zoom::ZoomEventManager> zoom_event_manager_;
   content::HostZoomMap* host_zoom_map_;
   std::unique_ptr<content::HostZoomMap::Subscription> zoom_subscription_;
-  std::string partition_key_;
   base::CallbackList<void(void)> default_zoom_changed_callbacks_;
+  base::CallbackList<void(void)> default_scope_changed_callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeZoomLevelPrefs);
 };
 
 #endif  // CHROME_BROWSER_UI_ZOOM_CHROME_ZOOM_LEVEL_PREFS_H_