Fix media crash in layout test

content/renderer/media/android/webmediaplayer_android.cc

Index: content/renderer/media/android/webmediaplayer_android.cc
diff --git a/content/renderer/media/android/webmediaplayer_android.cc b/content/renderer/media/android/webmediaplayer_android.cc
index 47da91c5ec22cdae047748f41701d2d2452411af..ce831451d850149599b063975f3b2843e573d813 100644
--- a/content/renderer/media/android/webmediaplayer_android.cc
+++ b/content/renderer/media/android/webmediaplayer_android.cc
@@ -137,8 +137,11 @@ WebMediaPlayerAndroid::WebMediaPlayerAndroid(
       is_playing_(false),
       needs_establish_peer_(true),
       has_size_info_(false),
+      // Compositor thread does not exist in layout tests.
       compositor_loop_(
-          RenderThreadImpl::current()->compositor_message_loop_proxy()),
+          RenderThreadImpl::current()->compositor_message_loop_proxy()
+              ? RenderThreadImpl::current()->compositor_message_loop_proxy()
+              : base::MessageLoopProxy::current()),
       stream_texture_factory_(factory),
       needs_external_surface_(false),
       video_frame_provider_client_(NULL),