Add flag that enable Encrypted Media Extensions on video elements.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 41132b061b897becdb0d16416f9e7696cdee0245..e4d1ba0f2815e4e6734c09d739680a0defd1f1eb 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -544,6 +544,9 @@ void RenderThreadImpl::EnsureWebKitInitialized() {
   WebKit::WebRuntimeFeatures::enableVideoTrack(
       command_line.HasSwitch(switches::kEnableVideoTrack));
 
+  WebKit::WebRuntimeFeatures::enableEncryptedMedia(
+      command_line.HasSwitch(switches::kEnableEncryptedMedia));
+
 #if defined(OS_CHROMEOS)
   // TODO(crogers): enable once Web Audio has been tested and optimized.
   WebRuntimeFeatures::enableWebAudio(false);