Support unprefixed EME in HTMLViewer.

Tested with:
out/GN/mojo_shell
http://<host>/LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html
--args-for='mojo://html_viewer --v=3 --enable-encrypted-media'

[email protected]
BUG=444205
TEST=See above.

Review URL: https://codereview.chromium.org/815293002

Cr-Commit-Position: refs/heads/master@{#309565}
diff --git a/mojo/services/html_viewer/webmediaplayer_factory.h b/mojo/services/html_viewer/webmediaplayer_factory.h
index 964ffac..687011a 100644
--- a/mojo/services/html_viewer/webmediaplayer_factory.h
+++ b/mojo/services/html_viewer/webmediaplayer_factory.h
@@ -17,6 +17,7 @@
 }
 
 namespace blink {
+class WebContentDecryptionModule;
 class WebMediaPlayer;
 class WebLocalFrame;
 class WebURL;
@@ -44,10 +45,12 @@
       bool enable_mojo_media_renderer);
   ~WebMediaPlayerFactory();
 
-  blink::WebMediaPlayer* CreateMediaPlayer(blink::WebLocalFrame* frame,
-                                           const blink::WebURL& url,
-                                           blink::WebMediaPlayerClient* client,
-                                           mojo::Shell* shell);
+  blink::WebMediaPlayer* CreateMediaPlayer(
+      blink::WebLocalFrame* frame,
+      const blink::WebURL& url,
+      blink::WebMediaPlayerClient* client,
+      blink::WebContentDecryptionModule* initial_cdm,
+      mojo::Shell* shell);
 
  private:
   const media::AudioHardwareConfig& GetAudioHardwareConfig();