media: Improve Widevine EncryptedMediaTest.PolicyCheck

This CL adds more detailed test case for EncryptedMediaTest.PolicyCheck
when using Widevine key system. Note that the test is bypassed on
ChromeOS since Widevine CDM on ChromeOS doesn't support this API yet.

Bug: 849846
Test: Add more detailed test case.
Change-Id: Iae08027f8fae25710dd5b997ff4942c234c04192
Reviewed-on: https://chromium-review.googlesource.com/1087438
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: John Rummell <jrummell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565466}

chrome/browser/media/encrypted_media_browsertest.cc

@@ -440,6 +440,13 @@ class EncryptedMediaTest
   }
 
   void TestPolicyCheck() {
+// TODO(crbug.com/847591): ChromeOS Widevine CDM does not support policy check
+// API yet. Remove this condition when the CDM is updated.
+#if defined(WIDEVINE_CDM_AVAILABLE) && defined(OS_CHROMEOS)
+    if (IsWidevine(key_system))
+      return;
+#endif  // defined(WIDEVINE_CDM_AVAILABLE) && defined(OS_CHROMEOS)
+
     base::StringPairs query_params;
     // We do not care about playback so choose an arbitrary media file.
     query_params.emplace_back("mediaFile", "bear-a_enc-a.webm");

media/test/data/eme_player_js/player_utils.js

@@ -64,58 +64,69 @@ PlayerUtils.registerEMEEventListeners = function(player) {
       });
     }
 
-    // Call getStatusForPolicy() and compare the result with |expectedResult|.
-    // |expectedResult| can be a valid key status, e.g. "usable", in which case
-    // getStatusForPolicy() should return a resolved promise. It can also be
-    // "rejected", in which getStatusForPolicy() should return a rejected
-    // promise.
-    function getStatusForHdcpPolicy(mediaKeys, hdcpVersion, expectedResult) {
-      return mediaKeys.getStatusForPolicy({minHdcpVersion: hdcpVersion})
-          .then(
-              keyStatus => {
-                if (keyStatus == expectedResult) {
-                  return Promise.resolve();
-                } else {
-                  return Promise.reject(
-                      'keyStatus ' + keyStatus + ' does not match ' +
-                      expectedResult);
-                }
-              },
-              error => {
-                if (expectedResult == 'rejected') {
-                  return Promise.resolve();
-                } else {
-                  return Promise.reject("Promise rejected unexpectedly.");
-                }
-              });
+    // Calls getStatusForPolicy() and returns a resolved promise if the result
+    // matches the |expectedResult|, whose value can be:
+    // - a valid key status, e.g. "usable", in which case getStatusForPolicy()
+    //   must be resolved with |expectedResult|.
+    // - "rejected", in which case getStatusForPolicy() must be rejected.
+    // - "resolved", in which case getStatusForPolicy() can be resolved by any
+    //   value.
+    async function getStatusForHdcpPolicy(
+        mediaKeys, hdcpVersion, expectedResult) {
+      try {
+        var keyStatus =
+            await mediaKeys.getStatusForPolicy({minHdcpVersion: hdcpVersion});
+        if (expectedResult == 'resolved' ||
+            (expectedResult != 'rejected' && keyStatus == expectedResult)) {
+          return true;
+        }
+
+        throw new Error(
+            'keyStatus ' + keyStatus + ' does not match ' + expectedResult);
+      } catch (e) {
+        if (expectedResult == 'rejected') {
+          return true;
+        }
+
+        throw new Error('Promise rejected unexpectedly: ' + e);
+      }
     }
 
+    // Tests HDCP policy check. Returns a resolved promise if all tests pass.
     function testGetStatusForHdcpPolicy(mediaKeys) {
       const keySystem = this.testConfig.keySystem;
       Utils.timeLog('Key system: ' + keySystem);
+
       if (keySystem == EXTERNAL_CLEARKEY) {
-        return Promise.resolve().then(function() {
-          return getStatusForHdcpPolicy(mediaKeys, "", "usable");
-        }).then(function() {
-          return getStatusForHdcpPolicy(mediaKeys, "hdcp-1.0", "usable");
-        }).then(function() {
-          return getStatusForHdcpPolicy(
-              mediaKeys, "hdcp-2.2", "output-restricted");
-        });
-      } else if (keySystem == CLEARKEY) {
-        return Promise.resolve().then(function () {
-          return getStatusForHdcpPolicy(mediaKeys, "", "rejected");
-        }).then(function () {
-          return getStatusForHdcpPolicy(mediaKeys, "hdcp-1.0", "rejected");
-        });
-      } else if (keySystem == WIDEVINE_KEYSYSTEM) {
-        // TODO(crbug.com/849846): Currently support on HDCP policy check by
-        // Widevine CDM varies on different platforms. Update this to test more
-        // specific behaviors.
-        return Promise.resolve();
-      } else {
-        return Promise.reject("Unsupported key system");
+        // ClearKeyCdm pretends the device is HDCP 2.0 compliant. See
+        // ClearKeyCdm::GetStatusForPolicy() for details.
+        return Promise.all([
+          getStatusForHdcpPolicy(mediaKeys, '', 'usable'),
+          getStatusForHdcpPolicy(mediaKeys, 'hdcp-1.0', 'usable'),
+          getStatusForHdcpPolicy(mediaKeys, 'hdcp-2.2', 'output-restricted'),
+        ]);
+      }
+
+      if (keySystem == CLEARKEY) {
+        // AesDecryptor does not support getStatusForPolicy() so the promise
+        // is always rejected.
+        return Promise.all([
+          getStatusForHdcpPolicy(mediaKeys, '', 'rejected'),
+          getStatusForHdcpPolicy(mediaKeys, 'hdcp-1.0', 'rejected'),
+        ]);
       }
+
+      if (keySystem == WIDEVINE_KEYSYSTEM) {
+        // Widevine CDM supports getStatusForPolicy() so the promise is always
+        // resolved. However the key status depends on the device's HDCP level
+        // so we cannot enforce it.
+        return Promise.all([
+          getStatusForHdcpPolicy(mediaKeys, '', 'usable'),
+          getStatusForHdcpPolicy(mediaKeys, 'hdcp-1.0', 'resolved'),
+        ]);
+      }
+
+      return Promise.reject('Unsupported key system');
     }
 
     try {
@@ -158,13 +169,13 @@ PlayerUtils.registerEMEEventListeners = function(player) {
         // new test js file once we figure out an easy way to separate the
         // requrestMediaKeySystemAccess() logic from the rest of this file.
         Utils.timeLog('Policy check test.');
-        player.access.createMediaKeys().then(function(mediaKeys) {
+        player.access.createMediaKeys().then(function (mediaKeys) {
           // Call getStatusForPolicy() before creating any MediaKeySessions.
           return testGetStatusForHdcpPolicy(mediaKeys);
-        }).then(function(result) {
+        }).then(function (result) {
           Utils.timeLog('Policy check test passed.');
           Utils.setResultInTitle(UNIT_TEST_SUCCESS);
-        }).catch(function(error) {
+        }).catch(function (error) {
           Utils.timeLog('Policy check test failed.');
           Utils.failTest(error, UNIT_TEST_FAILURE);
         });