Replace "enable-encrypted-media" flag with "disable-encrypted-media".

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 0d1615eb2980ecbf49c1d40da60b9fb5bf4d4f1b..baf70195012ef01a4828124a5fd9c0dee5cec03b 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -118,8 +118,8 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
     WebRuntimeFeatures::enableWebAudio(false);
 #endif
 
-  if (command_line.HasSwitch(switches::kEnableEncryptedMedia))
-    WebRuntimeFeatures::enableEncryptedMedia(true);
+  if (command_line.HasSwitch(switches::kDisableEncryptedMedia))
+    WebRuntimeFeatures::enableEncryptedMedia(false);
 
   if (command_line.HasSwitch(switches::kDisablePrefixedEncryptedMedia))
     WebRuntimeFeatures::enablePrefixedEncryptedMedia(false);