Autoplay: add document user activation flag in chrome://flags

content/public/common/web_preferences.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 CONTENT_PUBLIC_COMMON_WEB_PREFERENCES_H_
 #define CONTENT_PUBLIC_COMMON_WEB_PREFERENCES_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 49 matching lines @@
 // effects.
 enum class ProgressBarCompletion {
   LOAD_EVENT,
   RESOURCES_BEFORE_DCL,
   DOM_CONTENT_LOADED,
   RESOURCES_BEFORE_DCL_AND_SAME_ORIGIN_IFRAMES,
   LAST = RESOURCES_BEFORE_DCL_AND_SAME_ORIGIN_IFRAMES
 };
 
 // Defines the autoplay policy to be used. Should match the class in
 // WebSettings.h.

[nasko, 2017/06/05 23:48:11]

note: It would've been best if WebSettings.h change ensured that this file was
also changed.

[mlamouri (slow - plz ping), 2017/06/06 08:49:31]

FWIW, the changes were split on purpose so I could implement the feature in
Blink and write tests without having the feature exposed to our users. This
said, I don't know how we could have had an automatic way to make this check.
Any pointer?

 enum class AutoplayPolicy {
   kNoUserGestureRequired,
   kUserGestureRequired,
   kUserGestureRequiredForCrossOrigin,
+  kDocumentUserActivationRequired,
 };
 
 // The ISO 15924 script code for undetermined script aka Common. It's the
 // default used on WebKit's side to get/set a font setting when no script is
 // specified.
 CONTENT_EXPORT extern const char kCommonScript[];
 
 // A struct for managing blink's settings.
 //
 // Adding new values to this class probably involves updating
@@ skipping 216 matching lines @@
   // chrome, except for the cases where it would require lots of extra work for
   // the embedder to use the same default value.
   WebPreferences();
   WebPreferences(const WebPreferences& other);
   ~WebPreferences();
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_WEB_PREFERENCES_H_