Add a policy to re-enable deprecated web platform features.

content/public/common/renderer_preferences.h

 // Copyright (c) 2012 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.
 //
 // A struct for managing browser's settings that apply to the renderer or its
 // webview.  These differ from WebPreferences since they apply to Chromium's
 // glue layer rather than applying to just WebKit.
 //
 // Adding new values to this class probably involves updating
 // common/view_messages.h, browser/browser.cc, etc.
@@ skipping 27 matching lines @@
 };
 
 enum TapMultipleTargetsStrategy {
   TAP_MULTIPLE_TARGETS_STRATEGY_ZOOM = 0,
   TAP_MULTIPLE_TARGETS_STRATEGY_POPUP,
   TAP_MULTIPLE_TARGETS_STRATEGY_NONE,
 
   TAP_MULTIPLE_TARGETS_STRATEGY_MAX = TAP_MULTIPLE_TARGETS_STRATEGY_NONE,
 };
 
+enum RendererPreferencesDeprecatedFeatureEnum {
+  RENDERER_PREFERENCES_DEPRECATED_FEATURE_SHOW_MODAL_DIALOG,
+  RENDERER_PREFERENCES_DEPRECATED_FEATURE_COUNT,
+};
+
 struct CONTENT_EXPORT RendererPreferences {
   RendererPreferences();
   ~RendererPreferences();
 
   // Whether the renderer's current browser context accept drops from the OS
   // that result in navigations away from the current page.
   bool can_accept_load_drops;
 
   // Whether text should be antialiased.
   // Currently only used by Linux.
@@ skipping 83 matching lines @@
   // Disables rendering default error page when client choses to block a page.
   // Corresponds to net::ERR_BLOCKED_BY_CLIENT.
   bool disable_client_blocked_error_page;
 
   // Determines whether plugins are allowed to enter fullscreen mode.
   bool plugin_fullscreen_allowed;
 
   // Whether video-overlay (hole-punching) should be used for the embedded
   // encrypted video.  Currently only used by Android.
   bool use_video_overlay_for_embedded_encrypted_video;
+
+  // A bitset indicating which deprecated features to enable in the renderer.
+  std::vector<bool> deprecated_features_to_enable;

[Mattias Nissler (ping if slow), 2014/05/06 14:31:15]

Not sure whether it's better to put this here or in WebPreferences. Opinions?

[abarth-chromium, 2014/05/10 00:27:39]

These are going to map down to WebRuntimeFeatures, which I think we typically
represent using WebPreferences.

[Mattias Nissler (ping if slow), 2014/05/19 15:03:08]

OK, moved to WebPreferences.

 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_RENDERER_PREFERENCES_H_