Add Promises for EME (Chromium side)

media/base/cdm_promise.cc

Index: media/base/cdm_promise.cc
diff --git a/media/base/cdm_promise.cc b/media/base/cdm_promise.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7cffab15e4aff498dcb35fb5605c0ae520c08526
--- /dev/null
+++ b/media/base/cdm_promise.cc
@@ -0,0 +1,67 @@
+// 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/base/cdm_promise.h"
+
+#include "base/logging.h"
+
+namespace media {
+
+template <typename T>
+CdmPromise<T>::CdmPromise(base::Callback<void(const T&)> resolve_cb,
+                          PromiseRejectedCB rejected_cb)
+    : resolve_cb_(resolve_cb), rejected_cb_(rejected_cb), is_pending_(true) {
+  DCHECK(!resolve_cb_.is_null());
+  DCHECK(!rejected_cb_.is_null());
+}
+
+template <typename T>
+CdmPromise<T>::~CdmPromise() {
+  DCHECK(!is_pending_);
+}
+
+template <typename T>
+void CdmPromise<T>::resolve(const T& result) {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  resolve_cb_.Run(result);
+}
+
+template <typename T>
+void CdmPromise<T>::reject(MediaKeys::MediaKeysException exception_code,
+                           uint32 system_code,
+                           const std::string& error_message) {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  rejected_cb_.Run(exception_code, system_code, error_message);
+}
+
+CdmPromise<void>::CdmPromise(base::Callback<void()> resolve_cb,
+                             PromiseRejectedCB rejected_cb)
+    : resolve_cb_(resolve_cb), rejected_cb_(rejected_cb), is_pending_(true) {
+}
+
+CdmPromise<void>::~CdmPromise() {
+  DCHECK(!is_pending_);
+}
+
+void CdmPromise<void>::resolve() {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  resolve_cb_.Run();
+}
+
+void CdmPromise<void>::reject(MediaKeys::MediaKeysException exception_code,
+                              uint32 system_code,
+                              const std::string& error_message) {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  rejected_cb_.Run(exception_code, system_code, error_message);
+}
+
+// Explicit template instantiation for the Promises needed.
+template class MEDIA_EXPORT CdmPromise<std::string>;
+template class MEDIA_EXPORT CdmPromise<void>;
+
+}  // namespace media