Reland of name kDisableGestureRequirementForMediaPlayback and make it a test-only flag.

chrome/browser/flag_descriptions.h

 // Copyright 2017 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 CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 #define CHROME_BROWSER_FLAG_DESCRIPTIONS_H_
 
 // Includes needed for macros allowing conditional compilation of some strings.
 #include "build/build_config.h"
 #include "build/buildflag.h"
@@ skipping 697 matching lines @@
 extern const char kSslVersionMaxTls13[];
 
 // Title for the flag to enable Token Binding. Please do not translate 'Token
 // Binding'.
 extern const char kEnableTokenBindingName[];
 
 // Description for the flag to enable Token Binding. Please do not translate
 // 'Token Binding'.
 extern const char kEnableTokenBindingDescription[];
 
-// Title for the flag for gesture requiment for media playback
-extern const char kGestureRequirementForMediaPlaybackName[];
-
-// Description for the flag for gesture requiment for media playback
-extern const char kGestureRequirementForMediaPlaybackDescription[];
-
 // Description for the flag to adjust the default behaviour for document level
 // passive touch listeners.
 extern const char kPassiveDocumentEventListenersDescription[];
 
 // Name for the flag to adjust the default behaviour for document level passive
 // listeners.
 extern const char kPassiveDocumentEventListenersName[];
 
 // Description for the flag to adjust the default behaviour for passive touch
 // listeners during fling.
@@ skipping 2588 matching lines @@
 
 // Description of the autoplay policy that has no user gesture requirements.
 extern const char kAutoplayPolicyNoUserGestureRequired[];
 
 // Description of the autoplay policy that requires a user gesture.
 extern const char kAutoplayPolicyUserGestureRequired[];
 
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_