[Android] Added a runtime flag to enable autoplay of muted videos.

content/public/common/content_switches.cc

 // Copyright (c) 2012 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 "build/build_config.h"
 #include "content/public/common/content_switches.h"
 
 namespace switches {
 
 // The number of MSAA samples for canvas2D. Requires MSAA support by GPU to
@@ skipping 941 matching lines @@
 
 // Enables remote debug over HTTP on the specified socket name.
 const char kRemoteDebuggingSocketName[]     = "remote-debugging-socket-name";
 
 // Block ChildProcessMain thread of the renderer's ChildProcessService until a
 // Java debugger is attached.
 const char kRendererWaitForJavaDebugger[] = "renderer-wait-for-java-debugger";
 
 // Enables overscrolling for the OSK on Android.
 const char kEnableOSKOverscroll[]               = "enable-osk-overscroll";
+
+// Allow videos to autoplay without a user gesture if muted.
+const char kEnableAutoplayMutedVideos[] = "enable-autoplay-muted-videos";
 #endif
 
 // Enable the aggressive flushing of DOM Storage to minimize data loss.
 const char kEnableAggressiveDOMStorageFlushing[] =
     "enable-aggressive-domstorage-flushing";
 
 // Enable audio for desktop share.
 const char kDisableAudioSupportForDesktopShare[] =
     "disable-audio-support-for-desktop-share";
 
@@ skipping 72 matching lines @@
 const char kMemoryPressureThresholdsMb[] = "memory-pressure-thresholds-mb";
 
 // Enables the exporting of the tracing events to ETW. This is only supported on
 // Windows Vista and later.
 const char kTraceExportEventsToETW[] = "trace-export-events-to-etw";
 #endif
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches