media: Reenable TestPolicyCheck() on Windows for Widevine

The original problem has been fixed in the latest Widevine CDM.

Bug: 851027
Change-Id: I9aced3ea2152e33fcc8a5bcddc8a587c45dee6cc
Reviewed-on: https://chromium-review.googlesource.com/1154087Reviewed-by: Frank Liberato <liberato@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579615}

chrome/browser/media/encrypted_media_browsertest.cc

@@ -453,8 +453,7 @@ 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.
-// TODO(crbug.com/851027): Reenable this test on Windows after bug is fixed.
-#if defined(WIDEVINE_CDM_AVAILABLE) && (defined(OS_CHROMEOS) || defined(OS_WIN))
+#if defined(WIDEVINE_CDM_AVAILABLE) && defined(OS_CHROMEOS)
     if (IsWidevine(CurrentKeySystem())) {
       DVLOG(0) << "Skipping test due to HDCP policy check related bugs.";
       return;