Create autoplay policy flag and merge cross-origin autoplay blocking into it.

content/child/runtime_features.cc

Index: content/child/runtime_features.cc
diff --git a/content/child/runtime_features.cc b/content/child/runtime_features.cc
index ab8970952844ceb7d591792a01e32ebcf13ed779..f22e021185df813815ae2f957a358487fb1e4760 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -15,6 +15,7 @@
 #include "content/common/content_switches_internal.h"
 #include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
+#include "media/base/media_switches.h"
 #include "services/device/public/cpp/device_features.h"
 #include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "ui/gl/gl_switches.h"
@@ -49,10 +50,6 @@ static void SetRuntimeFeatureDefaultsForPlatform() {
   WebRuntimeFeatures::EnableMediaControlsOverlayPlayButton(true);
 #else  // defined(OS_ANDROID)
   WebRuntimeFeatures::EnableNavigatorContentUtils(true);
-  if (base::FeatureList::IsEnabled(
-          features::kCrossOriginMediaPlaybackRequiresUserGesture)) {
-    WebRuntimeFeatures::EnableAutoplayMutedVideos(true);
-  }
 #endif  // defined(OS_ANDROID)
 
 #if defined(OS_ANDROID) || defined(USE_AURA)
@@ -383,6 +380,13 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (base::FeatureList::IsEnabled(features::kIdleTimeSpellChecking))
     WebRuntimeFeatures::EnableFeatureFromString("IdleTimeSpellChecking", true);
 
+#if !defined(OS_ANDROID)
+  if (command_line.GetSwitchValueASCII(switches::kAutoplayPolicy) ==
+      switches::autoplay::kCrossOriginUserGestureRequiredPolicy) {
+    WebRuntimeFeatures::EnableAutoplayMutedVideos(true);
+  }
+#endif
+
   // Enable explicitly enabled features, and then disable explicitly disabled
   // ones.
   if (command_line.HasSwitch(switches::kEnableBlinkFeatures)) {