Add 'autoplay' content settings and expose it to Blink.

third_party/WebKit/public/web/WebContentSettingsClient.h

 // Copyright 2015 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 WebContentSettingsClient_h
 #define WebContentSettingsClient_h
 
 #include "public/platform/WebContentSettingCallbacks.h"
 
 namespace blink {
@@ skipping 60 matching lines @@
     virtual bool allowWriteToClipboard(bool defaultValue) { return defaultValue; }
 
     // Controls whether enabling Web Components API for this frame.
     virtual bool allowWebComponents(bool defaultValue) { return defaultValue; }
 
     // Controls whether to enable MutationEvents for this frame.
     // The common use case of this method is actually to selectively disable MutationEvents,
     // but it's been named for consistency with the rest of the interface.
     virtual bool allowMutationEvents(bool defaultValue) { return defaultValue; }
 
+    // Controls whether autoplay is allowed for this frame.
+    virtual bool allowAutoplay(bool defaultValue) { return defaultValue; }
+
     // Notifies the client that the frame would have instantiated a plugin if plugins were enabled.
     virtual void didNotAllowPlugins() { }
 
     // Notifies the client that the frame would have executed script if script were enabled.
     virtual void didNotAllowScript() { }
 
     // Notifies the client that the frame instantiated a keygen element.
     virtual void didUseKeygen() { }
 
     virtual ~WebContentSettingsClient() { }
 };
 
 } // namespace blink
 
 #endif // WebContentSettingsClient_h