EME: Allow temporary sessions to be removed for ClearKey only.

third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.cpp

Index: third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.cpp
diff --git a/third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.cpp b/third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.cpp
index 02128d9c900173584204fb5ef5453db69c960db1..7036d51910f88ae8e91d07aa26ef0a1fbba05537 100644
--- a/third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.cpp
+++ b/third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.cpp
@@ -813,37 +813,27 @@ ScriptPromise MediaKeySession::remove(ScriptState* script_state) {
   if (!is_callable_)
     return CreateRejectedPromiseNotCallable(script_state);
 
-  // 3. If the result of running the "Is persistent session type?" algorithm
-  //    on this object's session type is false, return a promise rejected
-  //    with a newly created TypeError.
-  if (!IsPersistentSessionType(session_type_)) {
-    return ScriptPromise::Reject(
-        script_state,
-        V8ThrowException::CreateTypeError(
-            script_state->GetIsolate(), "The session type is not persistent."));
-  }
-
-  // 4. Let promise be a new promise.
+  // 3. Let promise be a new promise.

[xhwang, 2017/04/21 18:00:28]

This change will also affect all key systems (e.g. Widevine) on all platforms. I
am not sure whether it's ready in those cases, e.g. WV on desktop/android,
ChromeCast, etc. And we probably should have browser tests covering those cases.

So, to avoid making this CL too big. Shall we limit this CL to only ClearKey?
Then we can fix it for Widevine in the next CL.

FWIW, to support WV on desktop, we need to update the CDM interface as well:
https://cs.chromium.org/chromium/src/media/cdm/api/content_decryption_module....

[jrummell, 2017/04/22 00:23:17]

Limited this to ClearKey only. Unfortunately there doesn't appear to be a common
place that knows about key_system and session type, so added
|is_persistent_session_| to webcontentdecryptionmodulesession_impl and checked
there.

   SimpleResultPromise* result = new SimpleResultPromise(script_state, this);
   ScriptPromise promise = result->Promise();
 
-  // 5. Run the following steps asynchronously (done in removeTask()).
+  // 4. Run the following steps asynchronously (done in removeTask()).
   pending_actions_.push_back(PendingAction::CreatePendingRemove(result));
   if (!action_timer_.IsActive())
     action_timer_.StartOneShot(0, BLINK_FROM_HERE);
 
-  // 6. Return promise.
+  // 5. Return promise.
   return promise;
 }
 
 void MediaKeySession::RemoveTask(ContentDecryptionModuleResult* result) {
-  // NOTE: Continue step 5 of MediaKeySession::remove().
+  // NOTE: Continue step 4 of MediaKeySession::remove().
   DVLOG(MEDIA_KEY_SESSION_LOG_LEVEL) << __func__ << "(" << this << ")";
 
-  // remove() in Chromium will execute steps 5.1 through 5.3.
+  // remove() in Chromium will execute steps 4.1 through 4.5.
   session_->Remove(result->Result());
 
-  // Last step (5.3.6 Resolve promise) will be done when |result| is resolved.
+  // Last step (4.5.6 Resolve promise) will be done when |result| is resolved.
 }
 
 void MediaKeySession::ActionTimerFired(TimerBase*) {