Refactor CdmPromise and related classes

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
index e10776dfd86230c0c4dc7b5216dd93786b9d78b9..ad509e204f09968e4efde1519047d9a5e768f656 100644
--- a/media/base/cdm_promise.cc
+++ b/media/base/cdm_promise.cc
@@ -4,17 +4,17 @@
 
 #include "media/base/cdm_promise.h"
 
-#include "base/bind.h"
 #include "base/logging.h"
-#include "base/metrics/histogram.h"
 
 namespace media {
 
-template <typename T>
+namespace {
+
+template <typename... T>
 struct CdmPromiseTraits {};
 
 template <>
-struct CdmPromiseTraits<void> {
+struct CdmPromiseTraits<> {
   static const CdmPromise::ResolveParameterType kType = CdmPromise::VOID_TYPE;
 };
 
@@ -29,131 +29,39 @@ struct CdmPromiseTraits<KeyIdsVector> {
       CdmPromise::KEY_IDS_VECTOR_TYPE;
 };
 
-CdmPromise::CdmPromise(ResolveParameterType parameter_type)
-    : parameter_type_(parameter_type), is_pending_(true) {
-}
+}  // namespace
 
-CdmPromise::CdmPromise(ResolveParameterType parameter_type,
-                       PromiseRejectedCB reject_cb)
-    : parameter_type_(parameter_type),
-      reject_cb_(reject_cb),
-      is_pending_(true) {
-  DCHECK(!reject_cb_.is_null());
-}
-
-CdmPromise::CdmPromise(ResolveParameterType parameter_type,
-                       PromiseRejectedCB reject_cb,
-                       const std::string& uma_name)
-    : parameter_type_(parameter_type),
-      reject_cb_(reject_cb),
-      is_pending_(true),
-      uma_name_(uma_name) {
-  DCHECK(!reject_cb_.is_null());
-  DCHECK(!uma_name_.empty());
+CdmPromise::CdmPromise() {
 }
 
 CdmPromise::~CdmPromise() {
-  DCHECK(!is_pending_);
-}
-
-static CdmPromise::ResultCodeForUMA ConvertExceptionToUMAResult(
-    MediaKeys::Exception exception_code) {
-  switch (exception_code) {
-    case MediaKeys::NOT_SUPPORTED_ERROR:
-      return CdmPromise::NOT_SUPPORTED_ERROR;
-    case MediaKeys::INVALID_STATE_ERROR:
-      return CdmPromise::INVALID_STATE_ERROR;
-    case MediaKeys::INVALID_ACCESS_ERROR:
-      return CdmPromise::INVALID_ACCESS_ERROR;
-    case MediaKeys::QUOTA_EXCEEDED_ERROR:
-      return CdmPromise::QUOTA_EXCEEDED_ERROR;
-    case MediaKeys::UNKNOWN_ERROR:
-      return CdmPromise::UNKNOWN_ERROR;
-    case MediaKeys::CLIENT_ERROR:
-      return CdmPromise::CLIENT_ERROR;
-    case MediaKeys::OUTPUT_ERROR:
-      return CdmPromise::OUTPUT_ERROR;
-  }
-  NOTREACHED();
-  return CdmPromise::UNKNOWN_ERROR;
-}
-
-void CdmPromise::reject(MediaKeys::Exception exception_code,
-                        uint32 system_code,
-                        const std::string& error_message) {
-  ReportResultToUMA(ConvertExceptionToUMAResult(exception_code));
-  reject_cb_.Run(exception_code, system_code, error_message);
-}
-
-void CdmPromise::ReportResultToUMA(ResultCodeForUMA result) {
-  DCHECK(is_pending_);
-  is_pending_ = false;
-  if (!uma_name_.empty()) {
-    base::LinearHistogram::FactoryGet(
-        uma_name_,
-        1,
-        NUM_RESULT_CODES,
-        NUM_RESULT_CODES + 1,
-        base::HistogramBase::kUmaTargetedHistogramFlag)->Add(result);
-  }
-}
-
-template <typename T>
-CdmPromiseTemplate<T>::CdmPromiseTemplate(
-    base::Callback<void(const T&)> resolve_cb,
-    PromiseRejectedCB reject_cb)
-    : CdmPromise(CdmPromiseTraits<T>::kType, reject_cb),
-      resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-}
-
-template <typename T>
-CdmPromiseTemplate<T>::CdmPromiseTemplate(
-    base::Callback<void(const T&)> resolve_cb,
-    PromiseRejectedCB reject_cb,
-    const std::string& uma_name)
-    : CdmPromise(CdmPromiseTraits<T>::kType, reject_cb, uma_name),
-      resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-}
-
-template <typename T>
-CdmPromiseTemplate<T>::CdmPromiseTemplate()
-    : CdmPromise(CdmPromiseTraits<T>::kType) {
-}
-
-template <typename T>
-void CdmPromiseTemplate<T>::resolve(const T& result) {
-  ReportResultToUMA(SUCCESS);
-  resolve_cb_.Run(result);
 }
 
-CdmPromiseTemplate<void>::CdmPromiseTemplate(base::Callback<void()> resolve_cb,
-                                             PromiseRejectedCB reject_cb)
-    : CdmPromise(CdmPromiseTraits<void>::kType, reject_cb),
-      resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
+template <typename... T>
+CdmPromiseTemplate<T...>::CdmPromiseTemplate()
+    : is_settled_(false) {
 }
 
-CdmPromiseTemplate<void>::CdmPromiseTemplate(base::Callback<void()> resolve_cb,
-                                             PromiseRejectedCB reject_cb,
-                                             const std::string& uma_name)
-    : CdmPromise(CdmPromiseTraits<void>::kType, reject_cb, uma_name),
-      resolve_cb_(resolve_cb) {
-  DCHECK(!resolve_cb_.is_null());
-  DCHECK(!uma_name_.empty());
+template <typename... T>
+CdmPromiseTemplate<T...>::~CdmPromiseTemplate() {
+  DCHECK(is_settled_);
 }
 
-CdmPromiseTemplate<void>::CdmPromiseTemplate()
-    : CdmPromise(CdmPromiseTraits<void>::kType) {
+template <typename... T>
+CdmPromise::ResolveParameterType
+CdmPromiseTemplate<T...>::GetResolveParameterType() const {
+  return CdmPromiseTraits<T...>::kType;
 }
 
-void CdmPromiseTemplate<void>::resolve() {
-  ReportResultToUMA(SUCCESS);
-  resolve_cb_.Run();
+template <typename... T>
+void CdmPromiseTemplate<T...>::MarkPromiseSettled() {
+  // Promise can only be settled once.
+  DCHECK(!is_settled_);
+  is_settled_ = true;
 }
 
-// Explicit template instantiation for the Promises needed.
+// Explicit template instantiation for the template Promises needed.
+template class MEDIA_EXPORT CdmPromiseTemplate<>;
 template class MEDIA_EXPORT CdmPromiseTemplate<std::string>;
 template class MEDIA_EXPORT CdmPromiseTemplate<KeyIdsVector>;