[Media controls] Add rotate-to-fullscreen gesture behind flag

chrome/browser/flag_descriptions.cc

 // 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.
 
 #include "chrome/browser/flag_descriptions.h"
 
 namespace flag_descriptions {
 
 //  Material Design version of chrome://bookmarks
 
@@ skipping 2572 matching lines @@
 
 //  Video fullscreen with orientation lock experiment strings.
 
 const char kVideoFullscreenOrientationLockName[] =
     "Lock screen orientation when playing a video fullscreen.";
 
 const char kVideoFullscreenOrientationLockDescription[] =
     "Lock the screen orientation of the device to match video orientation "
     "when a video goes fullscreen. Only on phones.";
 
+//  Video rotate-to-fullscreen experiment strings.
+
+const char kVideoRotateToFullscreenName[] =
+    "Rotate-to-fullscreen gesture for videos.";
+
+const char kVideoRotateToFullscreenDescription[] =
+    "Enter/exit fullscreen when device is rotated to/from the orientation of "
+    "the video. Only on phones.";
+
 //  Expensive background timer throttling flag
 
 const char kExpensiveBackgroundTimerThrottlingName[] =
     "Throttle expensive background timers";
 
 const char kExpensiveBackgroundTimerThrottlingDescription[] =
     "Enables intervention to limit CPU usage of background timers to 1%.";
 
 //  Enable default MediaSession flag
 
@@ skipping 432 matching lines @@
 
 const char kAutoplayPolicyNoUserGestureRequired[] =
     "No user gesture is required.";
 
 const char kAutoplayPolicyUserGestureRequired[] = "User gesture is required.";
 
 const char kAutoplayPolicyCrossOriginUserGestureRequired[] =
     "User gesture is required for cross-origin iframes.";
 
 }  // namespace flag_descriptions