Autoplay: use an autoplay policy setting in Blink.

third_party/WebKit/Source/core/frame/Settings.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights
  * reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 10 matching lines @@
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef Settings_h
 #define Settings_h
 
+#include <memory>
 #include "bindings/core/v8/V8CacheOptions.h"
 #include "bindings/core/v8/V8CacheStrategiesForCacheStorage.h"
 #include "core/CoreExport.h"
 #include "core/SettingsMacros.h"
 #include "core/editing/EditingBehaviorTypes.h"
 #include "core/editing/SelectionStrategy.h"
 #include "core/events/AddEventListenerOptionsDefaults.h"
 #include "core/frame/SettingsDelegate.h"
+#include "core/html/media/AutoplayPolicy.h"
 #include "core/html/track/TextTrackKindUserPreference.h"
 #include "core/loader/FrameLoaderTypes.h"
 #include "platform/Timer.h"
 #include "platform/fonts/GenericFontFamilySettings.h"
 #include "platform/geometry/IntSize.h"
 #include "platform/graphics/ImageAnimationPolicy.h"
 #include "platform/weborigin/KURL.h"
 #include "public/platform/PointerProperties.h"
 #include "public/platform/WebDisplayMode.h"
 #include "public/platform/WebViewportStyle.h"
-#include <memory>
 
 namespace blink {
 
 class CORE_EXPORT Settings {
   WTF_MAKE_NONCOPYABLE(Settings);
   USING_FAST_MALLOC(Settings);
 
  public:
   static std::unique_ptr<Settings> Create();
 
@@ skipping 32 matching lines @@
   GenericFontFamilySettings generic_font_family_settings_;
   IntSize text_autosizing_window_size_override_;
   bool text_autosizing_enabled_ : 1;
 
   SETTINGS_MEMBER_VARIABLES
 };
 
 }  // namespace blink
 
 #endif  // Settings_h