media: Reject pending CDM promise during destruction.

media/mojo/services/mojo_cdm_promise.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/mojo/services/mojo_cdm_promise.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 19 matching lines @@
 }
 
 template <typename... T>
 MojoCdmPromise<T...>::MojoCdmPromise(const CallbackType& callback)
     : callback_(callback) {
   DCHECK(!callback_.is_null());
 }
 
 template <typename... T>
 MojoCdmPromise<T...>::~MojoCdmPromise() {
-  if (!callback_.is_null())
-    DVLOG(1) << "Promise not resolved before destruction.";
+  if (callback_.is_null())
+    return;
+
+  std::string message =

[ddorwin, 2016/02/25 19:14:12]

We have the same code in 4 places. Does it make sense to have a
RejectDueToDestruction() in the base class?

[xhwang, 2016/02/25 19:53:11]

reject() is virtual and we have to call the reject() in the subclasses. When we
are in the dtor of the base class it's already too late.

We can share the messages somehow but that doesn't really help too much.

+      "Unfulfilled promise rejected automatically during destruction.";
+  DVLOG(1) << message;
+  reject(MediaKeys::INVALID_STATE_ERROR, 0, message);
 }
 
 template <typename... T>
 void MojoCdmPromise<T...>::resolve(const T&... result) {
   MarkPromiseSettled();
   interfaces::CdmPromiseResultPtr cdm_promise_result(
       interfaces::CdmPromiseResult::New());
   cdm_promise_result->success = true;
   callback_.Run(
       std::move(cdm_promise_result),
       mojo::TypeConverter<typename MojoTypeTrait<T>::MojoType, T>::Convert(
           result)...);
   callback_.reset();
 }
 
 template <typename... T>
 void MojoCdmPromise<T...>::reject(MediaKeys::Exception exception,
                                   uint32_t system_code,
                                   const std::string& error_message) {
   MarkPromiseSettled();
   callback_.Run(GetRejectResult(exception, system_code, error_message),
                 MojoTypeTrait<T>::DefaultValue()...);
   callback_.reset();
 }
 
 template class MojoCdmPromise<>;
 template class MojoCdmPromise<std::string>;
 
 }  // namespace media