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

media/base/media_switches.cc

Index: media/base/media_switches.cc
diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
index 571974cd77a5f13cc5d4085dac1d5f3cb2210c89..1769cff8ffbccd1692a74811ee9a091887951937 100644
--- a/media/base/media_switches.cc
+++ b/media/base/media_switches.cc
@@ -137,6 +137,12 @@
 // Default values are 150M for video and 12M for audio.
 const char kMSEAudioBufferSizeLimit[] = "mse-audio-buffer-size-limit";
 const char kMSEVideoBufferSizeLimit[] = "mse-video-buffer-size-limit";
+
+// Ignores all autoplay restrictions. It will ignore the current autoplay policy
+// and all restrictions such as playback in a background tab. It should only be
+// enabled for testing.
+const char kIgnoreAutoplayRestrictionsForTests[] =
+    "ignore-autoplay-restrictions";
 
 namespace autoplay {