Chromecast: change BrowserCdmCast threading model.

Per crbug/444930 discussion, BrowserCdm should generally remain on UI
thread. Interactions between the CMA pipeline and BrowserCdm should
remain thread-safe.

R=erickung@chromium.org,lcwu@chromium.org

Review URL: https://codereview.chromium.org/903083003

Cr-Commit-Position: refs/heads/master@{#315359}

chromecast/media/cdm/browser_cdm_cast.cc

@@ -9,11 +9,16 @@
 namespace chromecast {
 namespace media {
 
-BrowserCdmCast::BrowserCdmCast() {
+BrowserCdmCast::BrowserCdmCast()
+    : next_registration_id_(0) {
 }
 
 BrowserCdmCast::~BrowserCdmCast() {
-  player_tracker_.NotifyCdmUnset();
+  base::AutoLock auto_lock(callback_lock_);
+  for (std::map<uint32_t, base::Closure>::const_iterator it =
+       cdm_unset_callbacks_.begin(); it != cdm_unset_callbacks_.end(); ++it) {
+    it->second.Run();
+  }
 }
 
 void BrowserCdmCast::SetCallbacks(
@@ -31,11 +36,25 @@ void BrowserCdmCast::SetCallbacks(
 
 int BrowserCdmCast::RegisterPlayer(const base::Closure& new_key_cb,
                                    const base::Closure& cdm_unset_cb) {
-  return player_tracker_.RegisterPlayer(new_key_cb, cdm_unset_cb);
+  int registration_id = next_registration_id_++;
+  DCHECK(!new_key_cb.is_null());
+  DCHECK(!cdm_unset_cb.is_null());
+  {
+    base::AutoLock auto_lock(callback_lock_);
+    DCHECK(!ContainsKey(new_key_callbacks_, registration_id));
+    DCHECK(!ContainsKey(cdm_unset_callbacks_, registration_id));
+    new_key_callbacks_[registration_id] = new_key_cb;
+    cdm_unset_callbacks_[registration_id] = cdm_unset_cb;
+  }
+  return registration_id;
 }
 
 void BrowserCdmCast::UnregisterPlayer(int registration_id) {
-  player_tracker_.UnregisterPlayer(registration_id);
+  base::AutoLock auto_lock(callback_lock_);
+  DCHECK(ContainsKey(new_key_callbacks_, registration_id));
+  DCHECK(ContainsKey(cdm_unset_callbacks_, registration_id));
+  new_key_callbacks_.erase(registration_id);
+  cdm_unset_callbacks_.erase(registration_id);
 }
 
 void BrowserCdmCast::OnSessionMessage(const std::string& web_session_id,
@@ -68,7 +87,13 @@ void BrowserCdmCast::OnSessionKeysChange(
   session_keys_change_cb_.Run(web_session_id, true, cdm_keys_info.Pass());
 
   // Notify listeners of a new key.
-  player_tracker_.NotifyNewKey();
+  {
+    base::AutoLock auto_lock(callback_lock_);
+    for (std::map<uint32_t, base::Closure>::const_iterator it =
+         new_key_callbacks_.begin(); it != new_key_callbacks_.end(); ++it) {
+      it->second.Run();
+    }
+  }
 }
 
 }  // namespace media

chromecast/media/cdm/browser_cdm_cast.h

@@ -13,9 +13,9 @@
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
 #include "media/base/browser_cdm.h"
 #include "media/cdm/json_web_key.h"
-#include "media/cdm/player_tracker_impl.h"
 
 namespace chromecast {
 namespace media {
@@ -49,7 +49,7 @@ class BrowserCdmCast : public ::media::BrowserCdm {
   // |key_id|.
   // Returns null if |key_id| is not available.
   virtual scoped_refptr<DecryptContext> GetDecryptContext(
-      const std::string& key_id) const = 0;
+      const std::string& key_id) = 0;
 
  protected:
   void OnSessionMessage(const std::string& web_session_id,
@@ -66,7 +66,10 @@ class BrowserCdmCast : public ::media::BrowserCdm {
   ::media::SessionKeysChangeCB session_keys_change_cb_;
   ::media::SessionExpirationUpdateCB session_expiration_update_cb_;
 
-  ::media::PlayerTrackerImpl player_tracker_;
+  base::Lock callback_lock_;
+  uint32_t next_registration_id_;
+  std::map<uint32_t, base::Closure> new_key_callbacks_;
+  std::map<uint32_t, base::Closure> cdm_unset_callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserCdmCast);
 };

chromecast/media/cma/pipeline/av_pipeline_impl.cc

@@ -19,6 +19,7 @@
 #include "chromecast/media/cma/base/decoder_buffer_base.h"
 #include "chromecast/media/cma/pipeline/decrypt_util.h"
 #include "media/base/audio_decoder_config.h"
+#include "media/base/bind_to_current_loop.h"
 #include "media/base/decrypt_config.h"
 
 namespace chromecast {
@@ -187,8 +188,10 @@ void AvPipelineImpl::SetCdm(BrowserCdmCast* media_keys) {
 
   media_keys_ = media_keys;
   media_keys_callback_id_ = media_keys_->RegisterPlayer(
-      base::Bind(&AvPipelineImpl::OnCdmStateChanged, weak_this_),
-      base::Bind(&AvPipelineImpl::OnCdmDestroyed, weak_this_));
+      ::media::BindToCurrentLoop(
+          base::Bind(&AvPipelineImpl::OnCdmStateChanged, weak_this_)),
+      ::media::BindToCurrentLoop(
+          base::Bind(&AvPipelineImpl::OnCdmDestroyed, weak_this_)));
 }
 
 void AvPipelineImpl::OnEos() {

chromecast/media/cma/pipeline/media_pipeline_impl.cc

@@ -114,6 +114,7 @@ void MediaPipelineImpl::SetCdm(int cdm_id) {
 
 void MediaPipelineImpl::SetCdm(::media::BrowserCdm* media_keys) {
   CMALOG(kLogControl) << __FUNCTION__;
+  DCHECK(thread_checker_.CalledOnValidThread());
   audio_pipeline_->SetCdm(static_cast<BrowserCdmCast*>(media_keys));
   video_pipeline_->SetCdm(static_cast<BrowserCdmCast*>(media_keys));
 }