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

chrome/browser/flag_descriptions.cc

Index: chrome/browser/flag_descriptions.cc
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 18af4b8115408bb009a748367b64b1391ec4ca09..5289743653f564be756a860ef46aa3f4ee69a656 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -2595,6 +2595,15 @@ 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[] =