Encrypted Media: Implement IPC based SetCdm().

content/renderer/media/android/proxy_media_keys.cc

Index: content/renderer/media/android/proxy_media_keys.cc
diff --git a/content/renderer/media/android/proxy_media_keys.cc b/content/renderer/media/android/proxy_media_keys.cc
index 9734e815e785ab7963e77947edfa159ec00d8c89..09c2e0bdf5fc4341ae427d100f6697096ac7dfdb 100644
--- a/content/renderer/media/android/proxy_media_keys.cc
+++ b/content/renderer/media/android/proxy_media_keys.cc
@@ -29,6 +29,7 @@ ProxyMediaKeys::ProxyMediaKeys(
       session_closed_cb_(session_closed_cb),
       session_error_cb_(session_error_cb) {
   DCHECK(manager_);
+  DCHECK_NE(cdm_id, media::MediaKeys::kInvalidCdmId);
 }
 
 ProxyMediaKeys::~ProxyMediaKeys() {
@@ -86,6 +87,10 @@ void ProxyMediaKeys::ReleaseSession(uint32 session_id) {
   manager_->ReleaseSession(cdm_id_, session_id);
 }
 
+int ProxyMediaKeys::GetCdmId() {
+  return cdm_id_;
+}
+
 void ProxyMediaKeys::OnSessionCreated(uint32 session_id,
                                       const std::string& web_session_id) {
   session_created_cb_.Run(session_id, web_session_id);