Add setting to isolate zoom changes by default.

chrome/browser/ui/webui/options/content_settings_handler.h

Index: chrome/browser/ui/webui/options/content_settings_handler.h
diff --git a/chrome/browser/ui/webui/options/content_settings_handler.h b/chrome/browser/ui/webui/options/content_settings_handler.h
index 768ff702a69fd28cad905b27e7ff327f04276b14..8a630a01cb71a81020a254f935ae37055c347454 100644
--- a/chrome/browser/ui/webui/options/content_settings_handler.h
+++ b/chrome/browser/ui/webui/options/content_settings_handler.h
@@ -16,6 +16,7 @@
 #include "chrome/browser/pepper_flash_settings_manager.h"
 #include "chrome/browser/ui/webui/options/options_ui.h"
 #include "chrome/browser/ui/webui/options/pepper_flash_content_settings_utils.h"
+#include "chrome/browser/ui/zoom/chrome_zoom_level_prefs.h"
 #include "components/content_settings/core/browser/content_settings_observer.h"
 #include "components/content_settings/core/common/content_settings.h"
 #include "components/content_settings/core/common/content_settings_types.h"
@@ -255,6 +256,8 @@ class ContentSettingsHandler : public OptionsPageUIHandler,
 
   // content::HostZoomMap subscription.
   void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
+  // ChromeZoomLevelPrefs::DefaultZoomScopeSubscription subscription.
+  void OnZoomScopeChanged();
 
   void ShowFlashMediaLink(
       LinkType link_type, ContentSettingsType content_type, bool show);
@@ -265,6 +268,8 @@ class ContentSettingsHandler : public OptionsPageUIHandler,
 
   void UpdateProtectedContentExceptionsButton();
 
+  void UpdateZoomScopeExplanationVisibility();
+
   // Member variables ---------------------------------------------------------
 
   content::NotificationRegistrar notification_registrar_;
@@ -275,6 +280,8 @@ class ContentSettingsHandler : public OptionsPageUIHandler,
       host_zoom_map_subscription_;
   std::unique_ptr<content::HostZoomMap::Subscription>
       signin_host_zoom_map_subscription_;
+  std::unique_ptr<ChromeZoomLevelPrefs::DefaultZoomScopeSubscription>
+      default_zoom_scope_subscription_;
   ScopedObserver<HostContentSettingsMap, content_settings::Observer> observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSettingsHandler);