Bugzilla

(In reply to Jens Stutte [:jstutte] from comment #7)
> Other APIs we are working on to make them available in PBM are Cache API (bug 1714354, close to be enabled) and service workers (bug 1320796, needs a few months, still). It would be good if we could see some logging from the console when this happens to confirm those are related or not.

This is the error message:

```
Uncaught (in promise) 
Object { code: 7701, ec: 1003, Vc: undefined, Pm: undefined, Ky: undefined, message: "Unable to create media keys system access. Key system configuration is not supported", details: "Key system configuration is not supported", data: DOMException, wj: undefined, VWb: undefined, … }
```

Looks like `navigator.requestMediaKeySystemAccess` is failing on private browsing mode. The call being made is:

```js
navigator.requestMediaKeySystemAccess("com.widevine.alpha", [
  {
    "initDataTypes": [
      "cenc"
    ],
    "videoCapabilities": [
      {
        "contentType": "video/mp4;codecs=avc1.4d0028",
        "robustness": "SW_SECURE_DECODE"
      }
    ],
    "sessionTypes": [
      "temporary"
    ],
    "persistentState": "required"
  }
]);
```

And this indeed fails only on private browsing mode with `DOMException: Key system configuration is not supported`. As comment #0 already noted, bug 1334111 limited the access on PBM.

(In reply to Jens Stutte [:jstutte] from comment #7)
> Other APIs we are working on to make them available in PBM are Cache API (bug 1714354, close to be enabled) and service workers (bug 1320796, needs a few months, still). It would be good if we could see some logging from the console when this happens to confirm those are related or not.

This is the error message:

```
Uncaught (in promise) 
Object { code: 7701, ec: 1003, Vc: undefined, Pm: undefined, Ky: undefined, message: "Unable to create media keys system access. Key system configuration is not supported", details: "Key system configuration is not supported", data: DOMException, wj: undefined, VWb: undefined, … }
```

Looks like `navigator.requestMediaKeySystemAccess` is failing on private browsing mode. The call being made is:

```js
navigator.requestMediaKeySystemAccess("com.widevine.alpha", [
  {
    "initDataTypes": [
      "cenc"
    ],
    "videoCapabilities": [
      {
        "contentType": "video/mp4;codecs=avc1.4d0028",
        "robustness": "SW_SECURE_DECODE"
      }
    ],
    "sessionTypes": [
      "temporary"
    ],
    "persistentState": "required"
  }
]);
```

And this indeed fails only on private browsing mode with `DOMException: Key system configuration is not supported`. As comment #0 already noted, bug 1334111 limited [the access on PBM](https://searchfox.org/mozilla-central/rev/6f0792f9f3f1a6175ce1f8e318a8a0f51ba76dee/dom/media/eme/MediaKeySystemAccess.cpp#790-797).