media: Fix TestPolicyCheck() on ChromeOS

Fix a copy/paste error in the previous CL.

Bug: 849846
Change-Id: I32440d9c8a8e8879f262d6e3b8b51547301fcec2
Reviewed-on: https://chromium-review.googlesource.com/1093271
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: John Rummell <jrummell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565671}

chrome/browser/media/encrypted_media_browsertest.cc

@@ -443,7 +443,7 @@ class EncryptedMediaTest
 // 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))
+    if (IsWidevine(CurrentKeySystem()))
       return;
 #endif  // defined(WIDEVINE_CDM_AVAILABLE) && defined(OS_CHROMEOS)