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..73d5d6f171ba59272554bbb693e53e71b390e47f
--- /dev/null
+++ b/media/base/cdm_promise.cc
@@ -0,0 +1,75 @@
+// 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/bind.h"
+#include "base/logging.h"
+
+namespace media {
+
+CdmPromise::CdmPromise() : is_pending_(true) {
+}
+
+CdmPromise::CdmPromise(PromiseRejectedCB reject_cb)
+    : reject_cb_(reject_cb), is_pending_(true) {
+  DCHECK(!reject_cb_.is_null());
+}
+
+CdmPromise::~CdmPromise() {
+  DCHECK(!is_pending_);
+}
+
+void CdmPromise::reject(MediaKeys::Exception exception_code,
+                        uint32 system_code,
+                        const std::string& error_message) {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  reject_cb_.Run(exception_code, system_code, error_message);
+}
+
+template <typename T>
+CdmPromiseTemplate<T>::CdmPromiseTemplate(
+    base::Callback<void(const T&)> resolve_cb,
+    PromiseRejectedCB reject_cb)
+    : CdmPromise(reject_cb), resolve_cb_(resolve_cb) {
+  DCHECK(!resolve_cb_.is_null());
+}
+
+template <typename T>
+CdmPromiseTemplate<T>::~CdmPromiseTemplate() {
+  DCHECK(!is_pending_);
+}
+
+template <typename T>
+void CdmPromiseTemplate<T>::resolve(const T& result) {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  resolve_cb_.Run(result);
+}
+
+CdmPromiseTemplate<void>::CdmPromiseTemplate(base::Callback<void()> resolve_cb,
+                                             PromiseRejectedCB reject_cb)
+    : CdmPromise(reject_cb), resolve_cb_(resolve_cb) {
+  DCHECK(!resolve_cb_.is_null());
+}
+
+CdmPromiseTemplate<void>::CdmPromiseTemplate() {
+}
+
+CdmPromiseTemplate<void>::~CdmPromiseTemplate() {
+  DCHECK(!is_pending_);
+}
+
+void CdmPromiseTemplate<void>::resolve() {
+  DCHECK(is_pending_);
+  is_pending_ = false;
+  resolve_cb_.Run();
+}
+
+// Explicit template instantiation for the Promises needed.
+template class MEDIA_EXPORT CdmPromiseTemplate<std::string>;
+template class MEDIA_EXPORT CdmPromiseTemplate<void>;
+
+}  // namespace media