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

content/public/common/renderer_preferences.h

Index: content/public/common/renderer_preferences.h
diff --git a/content/public/common/renderer_preferences.h b/content/public/common/renderer_preferences.h
index 43e43c9e58931d42c780a9f283d3f811a4e21427..b92b38a660b1612ed4708cbfc4f874877f7b339c 100644
--- a/content/public/common/renderer_preferences.h
+++ b/content/public/common/renderer_preferences.h
@@ -45,6 +45,11 @@ enum TapMultipleTargetsStrategy {
   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();
@@ -148,6 +153,9 @@ struct CONTENT_EXPORT RendererPreferences {
   // 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