Reenable MediaDrmBridgeTest.Provision_Widevine test

On Android M devices, occasionally MediaDrm.getProvisionRequest()
throws, resulting in a flaky test. Reenabling the test for all
Android versions other than M.

Bug: 973096
Test: reenabled test passes
Change-Id: I87a78d737653cff3bd1a3727f0d673844cfa3db2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1669176
Commit-Queue: John Rummell <jrummell@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672619}

media/base/android/media_drm_bridge_unittest.cc

@@ -174,7 +174,7 @@ TEST_F(MediaDrmBridgeTest, CreateWithSecurityLevel_Widevine) {
   CreateWithoutSessionSupport(kWidevineKeySystem, kTestOrigin, kL1);
 }
 
-TEST_F(MediaDrmBridgeTest, DISABLED_Provision_Widevine) {
+TEST_F(MediaDrmBridgeTest, Provision_Widevine) {
   // Only test this if Widevine is supported. Otherwise
   // CreateWithoutSessionSupport() will return null and it can't be tested.
   if (!MediaDrmBridge::IsKeySystemSupported(kWidevineKeySystem)) {
@@ -189,6 +189,16 @@ TEST_F(MediaDrmBridgeTest, DISABLED_Provision_Widevine) {
     return;
   }
 
+  // On Android M occasionally MediaDrm.getProvisionRequest() throws and thus a
+  // request can not be generated. This has been fixed in Android N. As Android
+  // M is unlikely to be fixed, disabling this test if running on Android M.
+  // http://crbug.com/973096#c21
+  if (base::android::BuildInfo::GetInstance()->sdk_int() ==
+      base::android::SDK_VERSION_MARSHMALLOW) {
+    VLOG(0) << "Disabled for Android M.";
+    return;
+  }
+
   // Calling Provision() later should trigger a provisioning request. As we
   // can't pass the request to a license server,
   // MockProvisionFetcher::Retrieve() simply drops the request and never