Add browser test for EME persistent-usage-record session

This change adds a test to exercice the persistent-usage-record path
for EME. The new test create a PUR session and wait for the video to
end and verify that the license-release message contain the usage
record.

Bug: 1091502
Change-Id: I2d6347f39981d9eb1025d37ced254eb6aae766b1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2285250Reviewed-by: John Rummell <jrummell@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Commit-Queue: Alex St-Onge <alstonge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788870}

chrome/browser/media/encrypted_media_browsertest.cc

@@ -79,6 +79,7 @@ const char kExternalClearKeyStorageIdTestKeySystem[] =
 const char kNoSessionToLoad[] = "";
 #if BUILDFLAG(ENABLE_LIBRARY_CDMS)
 const char kPersistentLicense[] = "PersistentLicense";
+const char kPersistentUsageRecord[] = "PersistentUsageRecord";
 const char kUnknownSession[] = "UnknownSession";
 #endif
 
@@ -354,6 +355,9 @@ class ECKEncryptedMediaTest : public EncryptedMediaTestBase,
     command_line->AppendSwitchASCII(
         switches::kOverrideEnabledCdmInterfaceVersion,
         base::NumberToString(GetCdmInterfaceVersion()));
+    command_line->AppendSwitchASCII(
+        switches::kEnableBlinkFeatures,
+        "EncryptedMediaPersistentUsageRecordSession");
   }
 };
 
@@ -876,6 +880,11 @@ IN_PROC_BROWSER_TEST_P(ECKEncryptedMediaTest, LoadSessionAfterClose) {
                             media::kEnded);
 }
 
+IN_PROC_BROWSER_TEST_P(ECKEncryptedMediaTest, VerifyPersistentUsageRecord) {
+  TestPlaybackCase(kExternalClearKeyKeySystem, kPersistentUsageRecord,
+                   media::kEnded);
+}
+
 const char kExternalClearKeyDecryptOnlyKeySystem[] =
     "org.chromium.externalclearkey.decryptonly";
 

media/cdm/aes_decryptor.cc

@@ -407,15 +407,17 @@ void AesDecryptor::RemoveSession(const std::string& session_id,
   //           "persistent-license"
   //              Let message be a message containing or reflecting the record
   //              of license destruction.
+  //           "persistent-usage-record"
+  //              Not supported by AesDecryptor.
   std::vector<uint8_t> message;
-  if (it->second != CdmSessionType::kTemporary) {
+  if (it->second == CdmSessionType::kPersistentLicense) {
     // The license release message is specified in the spec:
     // https://w3c.github.io/encrypted-media/#clear-key-release-format.
     KeyIdList key_ids;
     key_ids.reserve(keys_info.size());
     for (const auto& key_info : keys_info)
       key_ids.push_back(key_info->key_id);
-    CreateKeyIdsInitData(key_ids, &message);
+    message = CreateLicenseReleaseMessage(key_ids);
   }
 
   // 4.5. Queue a task to run the following steps:
@@ -487,6 +489,12 @@ void AesDecryptor::Decrypt(StreamType stream_type,
     return;
   }
 
+  auto now = base::Time::Now();
+  if (first_decryption_time_.is_null())
+    first_decryption_time_ = now;
+
+  latest_decryption_time_ = now;
+
   DCHECK_EQ(decrypted->timestamp(), encrypted->timestamp());
   DCHECK_EQ(decrypted->duration(), encrypted->duration());
   std::move(decrypt_cb).Run(kSuccess, std::move(decrypted));
@@ -642,6 +650,27 @@ CdmKeysInfo AesDecryptor::GenerateKeysInfoList(
   return keys_info;
 }
 
+void AesDecryptor::GetRecordOfKeyUsage(const std::string& session_id,
+                                       KeyIdList& key_ids,
+                                       base::Time& first_decryption_time,
+                                       base::Time& latest_decryption_time) {
+  auto it = open_sessions_.find(session_id);
+  if (it == open_sessions_.end() ||
+      it->second != CdmSessionType::kPersistentUsageRecord) {
+    return;
+  }
+
+  base::AutoLock auto_lock(key_map_lock_);
+  for (const auto& item : key_map_) {
+    if (item.second->Contains(session_id)) {
+      key_ids.emplace_back(item.first.begin(), item.first.end());
+    }
+  }
+
+  first_decryption_time = first_decryption_time_;
+  latest_decryption_time = latest_decryption_time_;
+}
+
 AesDecryptor::DecryptionKey::DecryptionKey(const std::string& secret)
     : secret_(secret) {}
 

media/cdm/aes_decryptor.h

@@ -24,6 +24,7 @@
 #include "media/base/content_decryption_module.h"
 #include "media/base/decryptor.h"
 #include "media/base/media_export.h"
+#include "media/cdm/json_web_key.h"
 
 namespace crypto {
 class SymmetricKey;
@@ -176,6 +177,13 @@ class MEDIA_EXPORT AesDecryptor : public ContentDecryptionModule,
   CdmKeysInfo GenerateKeysInfoList(const std::string& session_id,
                                    CdmKeyInformation::KeyStatus status);
 
+  // Returns the record of key usage for persistent-usage-record session. Used
+  // by ClearKeyPersistentSessionCdm.
+  void GetRecordOfKeyUsage(const std::string& session_id,
+                           KeyIdList& key_ids,
+                           base::Time& first_decryption_time,
+                           base::Time& latest_decryption_time);
+
   // Callbacks for firing session events.
   SessionMessageCB session_message_cb_;
   SessionClosedCB session_closed_cb_;
@@ -196,6 +204,10 @@ class MEDIA_EXPORT AesDecryptor : public ContentDecryptionModule,
 
   CallbackRegistry<EventCB::RunType> event_callbacks_;
 
+  // First and latest decryption time for persistent-usage-record
+  base::Time first_decryption_time_ GUARDED_BY(key_map_lock_);
+  base::Time latest_decryption_time_ GUARDED_BY(key_map_lock_);
+
   DISALLOW_COPY_AND_ASSIGN(AesDecryptor);
 };
 

media/cdm/json_web_key.cc

@@ -338,10 +338,8 @@ void CreateLicenseRequest(const KeyIdList& key_ids,
   license->swap(result);
 }
 
-void CreateKeyIdsInitData(const KeyIdList& key_ids,
-                          std::vector<uint8_t>* init_data) {
-  // Create the init_data.
-  auto dictionary = std::make_unique<base::DictionaryValue>();
+void AddKeyIdsToDictionary(const KeyIdList& key_ids,
+                           base::DictionaryValue* dictionary) {
   auto list = std::make_unique<base::ListValue>();
   for (const auto& key_id : key_ids) {
     std::string key_id_string;
@@ -353,15 +351,64 @@ void CreateKeyIdsInitData(const KeyIdList& key_ids,
     list->AppendString(key_id_string);
   }
   dictionary->Set(kKeyIdsTag, std::move(list));
+}
 
+std::vector<uint8_t> SerializeDictionaryToVector(
+    const base::DictionaryValue* dictionary) {
   // Serialize the dictionary as a string.
   std::string json;
   JSONStringValueSerializer serializer(&json);
   serializer.Serialize(*dictionary);
 
   // Convert the serialized data into std::vector and return it.
-  std::vector<uint8_t> result(json.begin(), json.end());
-  init_data->swap(result);
+  return std::vector<uint8_t>(json.begin(), json.end());
+}
+
+void CreateKeyIdsInitData(const KeyIdList& key_ids,
+                          std::vector<uint8_t>* init_data) {
+  // Create the init_data.
+  auto dictionary = std::make_unique<base::DictionaryValue>();
+  AddKeyIdsToDictionary(key_ids, dictionary.get());
+
+  auto data = SerializeDictionaryToVector(dictionary.get());
+  init_data->swap(data);
+}
+
+// The format is a JSON object. For sessions of type "persistent-license" and
+// "persistent-usage-record", the object shall contain the following member:
+//
+//    "kids"
+//      An array of key IDs. Each element of the array is the base64url encoding
+//      of the octet sequence containing the key ID value.
+//
+// For sessions of type "persistent-usage-record" the object shall also contain
+// the following members:
+//
+//    "firstTime"
+//      The first decryption time expressed as a number giving the time, in
+//      milliseconds since 01 January, 1970 UTC.
+//    "latestTime"
+//      The latest decryption time expressed as a number giving the time, in
+//      milliseconds since 01 January,
+// 1970 UTC. https://w3c.github.io/encrypted-media/#clear-key-release-format
+std::vector<uint8_t> CreateLicenseReleaseMessage(
+    const KeyIdList& key_ids,
+    const base::Time first_decrypt_time,
+    const base::Time latest_decrypt_time) {
+  // Create the init_data.
+  auto dictionary = std::make_unique<base::DictionaryValue>();
+  AddKeyIdsToDictionary(key_ids, dictionary.get());
+
+  if (!first_decrypt_time.is_null() && !latest_decrypt_time.is_null()) {
+    // Persistent-Usage-Record
+    // Time need to be millisecond since 01 January, 1970 UTC
+    dictionary->SetDouble("firstTime",
+                          first_decrypt_time.ToJsTimeIgnoringNull());
+    dictionary->SetDouble("latestTime",
+                          latest_decrypt_time.ToJsTimeIgnoringNull());
+  }
+
+  return SerializeDictionaryToVector(dictionary.get());
 }
 
 bool ExtractFirstKeyIdFromLicenseRequest(const std::vector<uint8_t>& license,

media/cdm/json_web_key.h

@@ -11,6 +11,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/time/time.h"
 #include "media/base/media_export.h"
 
 namespace media {
@@ -94,6 +95,11 @@ MEDIA_EXPORT void CreateLicenseRequest(const KeyIdList& key_ids,
 MEDIA_EXPORT void CreateKeyIdsInitData(const KeyIdList& key_ids,
                                        std::vector<uint8_t>* key_ids_init_data);
 
+MEDIA_EXPORT std::vector<uint8_t> CreateLicenseReleaseMessage(
+    const KeyIdList& key_ids,
+    const base::Time first_decrypt_time = base::Time(),
+    const base::Time latest_decrypt_time = base::Time());
+
 // Extract the first key from the license request message. Returns true if
 // |license| is a valid license request and contains at least one key,
 // otherwise false and |first_key| is not touched.

media/cdm/library_cdm/clear_key_cdm/clear_key_persistent_session_cdm.cc

@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "media/base/cdm_promise.h"
+#include "media/cdm/json_web_key.h"
 
 namespace media {
 
@@ -94,9 +95,12 @@ ClearKeyPersistentSessionCdm::ClearKeyPersistentSessionCdm(
     const SessionClosedCB& session_closed_cb,
     const SessionKeysChangeCB& session_keys_change_cb,
     const SessionExpirationUpdateCB& session_expiration_update_cb)
-    : cdm_host_proxy_(cdm_host_proxy), session_closed_cb_(session_closed_cb) {
+    : cdm_host_proxy_(cdm_host_proxy),
+      session_message_cb_(session_message_cb),
+      session_closed_cb_(session_closed_cb) {
   cdm_ = base::MakeRefCounted<AesDecryptor>(
-      session_message_cb,
+      base::Bind(&ClearKeyPersistentSessionCdm::OnSessionMessage,
+                 weak_factory_.GetWeakPtr()),
       base::Bind(&ClearKeyPersistentSessionCdm::OnSessionClosed,
                  weak_factory_.GetWeakPtr()),
       session_keys_change_cb, session_expiration_update_cb);
@@ -116,7 +120,10 @@ void ClearKeyPersistentSessionCdm::CreateSessionAndGenerateRequest(
     const std::vector<uint8_t>& init_data,
     std::unique_ptr<NewSessionCdmPromise> promise) {
   std::unique_ptr<NewSessionCdmPromise> new_promise;
-  if (session_type != CdmSessionType::kPersistentLicense) {
+  // TODO(crbug.com/1102976) Add browser test for loading EME
+  // persistent-usage-record session
+  if (session_type == CdmSessionType::kTemporary ||
+      session_type == CdmSessionType::kPersistentUsageRecord) {
     new_promise = std::move(promise);
   } else {
     // Since it's a persistent session, we need to save the session ID after
@@ -294,7 +301,32 @@ void ClearKeyPersistentSessionCdm::RemoveSession(
   auto it = persistent_sessions_.find(session_id);
   if (it == persistent_sessions_.end()) {
     // Not a persistent session, so simply pass the request on.
+
+    // TODO(crbug.com/1102976) Add test for loading PUR session
+    // Query the record of key usage before calling remove as RemoveSession will
+    // delete the keys. Steps from
+    // https://w3c.github.io/encrypted-media/#remove. 4.4.1.2 Follow the steps
+    // for the value of this object's session type
+    //           "persistent-usage-record"
+    //              Let message be a message containing or reflecting this
+    //              object's record of key usage.
+    KeyIdList key_ids;
+    base::Time first_decryption_time;
+    base::Time latest_decryption_time;
+    cdm_->GetRecordOfKeyUsage(session_id, key_ids, first_decryption_time,
+                              latest_decryption_time);
     cdm_->RemoveSession(session_id, std::move(promise));
+
+    // Both times will be null if the session type is not PUR.
+    if (!first_decryption_time.is_null() && !latest_decryption_time.is_null()) {
+      std::vector<uint8_t> message = CreateLicenseReleaseMessage(
+          key_ids, first_decryption_time, latest_decryption_time);
+      // EME spec specifies that the message event should be fired before the
+      // promise is resolve but since this is only for testing we can leave this
+      // here.
+      session_message_cb_.Run(session_id, CdmMessageType::LICENSE_RELEASE,
+                              message);
+    }
     return;
   }
 
@@ -336,7 +368,6 @@ void ClearKeyPersistentSessionCdm::OnFileWrittenForRemoveSession(
     std::unique_ptr<SimpleCdmPromise> promise,
     bool success) {
   DCHECK(success);
-  cdm_->RemoveSession(session_id, std::move(promise));
 }
 
 CdmContext* ClearKeyPersistentSessionCdm::GetCdmContext() {
@@ -354,4 +385,11 @@ void ClearKeyPersistentSessionCdm::OnSessionClosed(
   session_closed_cb_.Run(session_id);
 }
 
+void ClearKeyPersistentSessionCdm::OnSessionMessage(
+    const std::string& session_id,
+    CdmMessageType message_type,
+    const std::vector<uint8_t>& message) {
+  session_message_cb_.Run(session_id, message_type, message);
+}
+
 }  // namespace media

media/cdm/library_cdm/clear_key_cdm/clear_key_persistent_session_cdm.h

@@ -101,10 +101,15 @@ class ClearKeyPersistentSessionCdm : public ContentDecryptionModule {
   // sessions if it was a persistent session.
   void OnSessionClosed(const std::string& session_id);
 
+  void OnSessionMessage(const std::string& session_id,
+                        CdmMessageType message_type,
+                        const std::vector<uint8_t>& message);
+
   scoped_refptr<AesDecryptor> cdm_;
   CdmHostProxy* const cdm_host_proxy_ = nullptr;
 
   // Callbacks for firing session events. Other events aren't intercepted.
+  SessionMessageCB session_message_cb_;
   SessionClosedCB session_closed_cb_;
 
   // Keep track of current open persistent sessions.

media/test/data/eme_player.html

@@ -103,7 +103,11 @@
 
       Utils.timeLog('waiting for video to end.');
       video.removeEventListener('ended', Utils.failTest);
-      Utils.installTitleEventHandler(video, 'ended');
+      if (testConfig.sessionToLoad == "PersistentUsageRecord") {
+        video.addEventListener('ended', onEnded);
+      } else {
+        Utils.installTitleEventHandler(video, 'ended');
+      }
       video.removeEventListener('timeupdate', onTimeUpdate);
     }
 
@@ -129,6 +133,16 @@
       Utils.timeLog('Event: ' + e.type + ', hidden: ' + document.hidden);
     }
 
+    function onEnded(e) {
+      Utils.timeLog('Event: ' + e.type);
+      PlayerUtils.removeSession(player).then(function() {
+        Utils.setResultInTitle('ENDED');
+      }).catch(function(error) {
+        Utils.timeLog(error);
+        Utils.failTest('Failed PlayerUtils.removeSession');
+      });
+    }
+
     function play(video, playTwice) {
       Utils.timeLog('Starting play, hidden: ' + document.hidden);
       video.addEventListener('canplay', onLogEvent);

media/test/data/eme_player_js/player_utils.js

@@ -54,6 +54,7 @@ PlayerUtils.registerEMEEventListeners = function(player) {
         player.video.receivedKeyMessage = true;
         if (message.messageType == 'license-request' ||
             message.messageType == 'license-renewal' ||
+            message.messageType == 'license-release' ||
             message.messageType == 'individualization-request') {
           player.video.receivedMessageTypes.add(message.messageType);
         } else {
@@ -140,7 +141,8 @@ PlayerUtils.registerEMEEventListeners = function(player) {
     }
 
     try {
-      if (player.testConfig.sessionToLoad) {
+      if (player.testConfig.sessionToLoad &&
+          player.testConfig.sessionToLoad != 'PersistentUsageRecord') {
         // Create a session to load using a new MediaKeys.
         // TODO(jrummell): Add a test that covers remove().
         player.access.createMediaKeys()
@@ -190,10 +192,16 @@ PlayerUtils.registerEMEEventListeners = function(player) {
           Utils.failTest(error, UNIT_TEST_FAILURE);
         });
       } else {
-        Utils.timeLog('Creating new media key session for initDataType: ' +
-                      message.initDataType + ', initData: ' +
-                      Utils.getHexString(new Uint8Array(message.initData)));
-        player.session = message.target.mediaKeys.createSession();
+        Utils.timeLog(
+            'Creating new media key session for initDataType: ' +
+            message.initDataType + ', initData: ' +
+            Utils.getHexString(new Uint8Array(message.initData)));
+        if (player.testConfig.sessionToLoad == 'PersistentUsageRecord') {
+          player.session =
+              message.target.mediaKeys.createSession('persistent-usage-record');
+        } else {
+          player.session = message.target.mediaKeys.createSession();
+        }
         addMediaKeySessionListeners(player.session);
         player.session.generateRequest(message.initDataType, message.initData)
             .catch(function(error) {
@@ -259,6 +267,9 @@ PlayerUtils.registerEMEEventListeners = function(player) {
       player.testConfig.keySystem == STORAGE_ID_TEST_KEYSYSTEM) {
     config.persistentState = 'required';
     config.sessionTypes = ['temporary', 'persistent-license'];
+    if (player.testConfig.sessionToLoad == 'PersistentUsageRecord') {
+      config.sessionTypes.push('persistent-usage-record');
+    }
   }
 
   return navigator
@@ -326,3 +337,27 @@ PlayerUtils.createPlayer = function(video, testConfig) {
   var Player = getPlayerType(testConfig.keySystem);
   return new Player(video, testConfig);
 };
+
+PlayerUtils.removeSession = async function(player) {
+  // Once remove() is called, another 'keystatuseschange' and 'message' events
+  // will happen.
+  const waitForKeyStatusChangePromise =
+      Utils.waitForEvent(player.session, 'keystatuseschange');
+
+  const waitForMessagePromise = Utils.waitForEvent(
+      player.session, 'message', function(e, resolve, reject) {
+        Utils.timeLog(e.messageType);
+        if (e.messageType == 'license-release' &&
+            player.testConfig.sessionToLoad == 'PersistentUsageRecord') {
+          Utils.verifyUsageRecord(e.message);
+        }
+        // TODO: verify license-release message for persistent-license session
+        resolve();
+      });
+
+  Utils.timeLog('Calling remove()');
+  const removePromise = player.session.remove();
+
+  return Promise.all(
+      [removePromise, waitForKeyStatusChangePromise, waitForMessagePromise]);
+}

media/test/data/eme_player_js/utils.js

@@ -86,16 +86,16 @@ Utils.createKeyIdsInitializationData = function(keyId) {
   return Utils.convertToUint8Array(initData);
 };
 
+function convertToString(data) {
+  return String.fromCharCode.apply(null, Utils.convertToUint8Array(data));
+}
+
 Utils.extractFirstLicenseKeyId = function(message) {
   // Decodes data (Uint8Array) from base64url string.
   function base64urlDecode(data) {
     return atob(data.replace(/\-/g, "+").replace(/\_/g, "/"));
   }
 
-  function convertToString(data) {
-    return String.fromCharCode.apply(null, Utils.convertToUint8Array(data));
-  }
-
   try {
     var json = JSON.parse(convertToString(message));
     // Decode the first element of 'kids', return it as an Uint8Array.
@@ -106,7 +106,31 @@ Utils.extractFirstLicenseKeyId = function(message) {
   }
 };
 
-Utils.documentLog = function(log, success, time) {
+Utils.verifyUsageRecord =
+    function(message) {
+  try {
+    var json = JSON.parse(convertToString(message));
+    var first_decrypt_time = new Date(json.firstTime);
+    var last_decrypt_time = new Date(json.latestTime);
+    Utils.timeLog('First decrypt time: ' + first_decrypt_time.toISOString());
+    Utils.timeLog('Last decrypt time: ' + last_decrypt_time.toISOString());
+
+    var delta = json.latestTime - json.firstTime;
+    // The video used for the tests is roughly 2.5 seconds.
+    if (delta < 2000 || delta > 3000) {
+      Utils.failTest(
+          'The usage record reported by the CDM was not in the' +
+          'expected range')
+    }
+
+  } catch (error) {
+    Utils.failTest(
+        'Fail to extract first decrypt time from license-release' +
+        'message');
+  }
+}
+
+    Utils.documentLog = function(log, success, time) {
   if (!docLogs)
     return;
   time = time || Utils.getCurrentTimeString();