Initialize the CDM asynchronously

media/blink/webmediaplayer_impl.cc

Index: media/blink/webmediaplayer_impl.cc
diff --git a/media/blink/webmediaplayer_impl.cc b/media/blink/webmediaplayer_impl.cc
index e8eec4c5ef6217d98b8667e427f7d1d57b936d17..15829106aade764d2cdb00544d5cef8be89fea80 100644
--- a/media/blink/webmediaplayer_impl.cc
+++ b/media/blink/webmediaplayer_impl.cc
@@ -699,7 +699,10 @@ void WebMediaPlayerImpl::OnWaitingForDecryptionKey() {
 
 void WebMediaPlayerImpl::SetCdm(const CdmAttachedCB& cdm_attached_cb,

[sandersd (OOO until July 31), 2015/04/27 20:17:48]

I'm not very familiar with how this happens, can you quickly describe how we get
here? Thanks!

[jrummell, 2015/04/27 21:24:38]

This is a CB passed down through ProxyDecryptor::CreateCdm(). When
initialization is complete, it is called. Previous CLs could provide NULL (see
ProxyDecryptor::OnCdmCreated(), line 96), but it looks like that path was never
executed (at least in the tests).

                                 CdmContext* cdm_context) {
-  pipeline_.SetCdm(cdm_context, cdm_attached_cb);
+  // The CDM may fail to create, so no need to tell the pipeline that a CDM
+  // is attached.
+  if (cdm_context)
+    pipeline_.SetCdm(cdm_context, cdm_attached_cb);
 }
 
 void WebMediaPlayerImpl::OnCdmAttached(