media: Make MediaKeys ref-counted.

chromecast/media/cdm/browser_cdm_cast.cc

Index: chromecast/media/cdm/browser_cdm_cast.cc
diff --git a/chromecast/media/cdm/browser_cdm_cast.cc b/chromecast/media/cdm/browser_cdm_cast.cc
index fa4195ad3c9cafb55bda1672a0c2a1af860e0b08..5051cf43ea6cca1d7fb995900a1947a8451a50f7 100644
--- a/chromecast/media/cdm/browser_cdm_cast.cc
+++ b/chromecast/media/cdm/browser_cdm_cast.cc
@@ -89,7 +89,7 @@ void BrowserCdmCast::Initialize(
     const ::media::SessionExpirationUpdateCB& session_expiration_update_cb) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  player_tracker_impl_.reset(new ::media::PlayerTrackerImpl);
+  player_tracker_impl_.reset(new ::media::PlayerTrackerImpl());
 
   session_message_cb_ = session_message_cb;
   session_closed_cb_ = session_closed_cb;
@@ -154,24 +154,16 @@ void BrowserCdmCast::OnSessionKeysChange(
                  base::Unretained(browser_cdm_cast_.get()), ##__VA_ARGS__))
 
 BrowserCdmCastUi::BrowserCdmCastUi(
-    scoped_ptr<BrowserCdmCast> browser_cdm_cast,
+    const scoped_refptr<BrowserCdmCast>& browser_cdm_cast,
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
-    : browser_cdm_cast_(browser_cdm_cast.Pass()), task_runner_(task_runner) {
-}
+    : browser_cdm_cast_(browser_cdm_cast), task_runner_(task_runner) {}
 
 BrowserCdmCastUi::~BrowserCdmCastUi() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  task_runner_->DeleteSoon(FROM_HERE, browser_cdm_cast_.release());
-}
-
-int BrowserCdmCastUi::RegisterPlayer(const base::Closure& new_key_cb,
-                                     const base::Closure& cdm_unset_cb) {
-  NOTREACHED() << "RegisterPlayer should be called on BrowserCdmCast";
-  return -1;
-}
-
-void BrowserCdmCastUi::UnregisterPlayer(int registration_id) {
-  NOTREACHED() << "UnregisterPlayer should be called on BrowserCdmCast";
+  browser_cdm_cast_->AddRef();
+  BrowserCdmCast* raw_cdm = browser_cdm_cast_.get();
+  browser_cdm_cast_ = nullptr;
+  task_runner_->ReleaseSoon(FROM_HERE, raw_cdm);

[halliwell, 2015/10/30 01:50:51]

Seems that we should assert that it HasOneRef before we call ReleaseSoon (if I'm
understanding correctly that this is intended to be a deterministic destruction
path still).

[xhwang, 2015/10/30 04:50:16]

For now yes. In the future, if the CMA pipeline could also hods a ref-count to
the browser_cdm_cast, then the ref count could be >1. I am reluctant to add it
here since that really is the implementation detail of the player (pipeline),
and is not a part of the EME stack.

 }
 
 BrowserCdmCast* BrowserCdmCastUi::browser_cdm_cast() const {