media: Add UMA to record time to GenerateRequest and LoadSession

media/blink/new_session_cdm_result_promise.h

 // 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.
 
 #ifndef MEDIA_BLINK_NEW_SESSION_CDM_RESULT_PROMISE_H_
 #define MEDIA_BLINK_NEW_SESSION_CDM_RESULT_PROMISE_H_
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "media/base/cdm_promise.h"
 #include "media/blink/media_blink_export.h"
 #include "third_party/WebKit/public/platform/WebContentDecryptionModuleResult.h"
 
 namespace media {
 
 enum class SessionInitStatus {
   // Error creating the session.
   UNKNOWN_STATUS,
 
@@ skipping 13 matching lines @@
 
 // Special class for resolving a new session promise. Resolving a new session
 // promise returns the session ID (as a string), but the blink promise needs
 // to get passed a SessionStatus. This class converts the session id to a
 // SessionStatus by calling |new_session_created_cb|.
 class MEDIA_BLINK_EXPORT NewSessionCdmResultPromise
     : public CdmPromiseTemplate<std::string> {
  public:
   NewSessionCdmResultPromise(
       const blink::WebContentDecryptionModuleResult& result,
+      const std::string& key_system_uma_prefix,
       const std::string& uma_name,
       const SessionInitializedCB& new_session_created_cb);
   ~NewSessionCdmResultPromise() override;
 
   // CdmPromiseTemplate<T> implementation.
   void resolve(const std::string& session_id) override;
   void reject(CdmPromise::Exception exception_code,
               uint32_t system_code,
               const std::string& error_message) override;
 
  private:
   blink::WebContentDecryptionModuleResult web_cdm_result_;
 
-  // UMA name to report result to.
+  // UMA prefix and name to report result and time to.
+  std::string key_system_uma_prefix_;
   std::string uma_name_;
 
   // Called on resolve() to convert the session ID into a SessionInitStatus to
   // be reported to blink.
   SessionInitializedCB new_session_created_cb_;
 
+  // Time when |this| is created.
+  base::TimeTicks creation_time_;
+
   DISALLOW_COPY_AND_ASSIGN(NewSessionCdmResultPromise);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_NEW_SESSION_CDM_RESULT_PROMISE_H_