Adds some integration with firefox.

This is still rather unstable, but it runs.

browser/profile/gmp-widevinecdm/4.10.2209.1/LICENSE.txt

@@ -0,0 +1,9 @@
+"Google Inc. and its affiliates ("Google") own all legal right, title and
+interest in and to the content decryption module software ("Software") and
+related documentation, including any intellectual property rights in the
+Software. You may not use, modify, sell, or otherwise distribute the Software
+without a separate license agreement with Google.  The Software is not open
+source software.
+
+If you are interested in licensing the Software, please contact
+widevine@google.com.

browser/profile/gmp-widevinecdm/4.10.2209.1/manifest.json

@@ -0,0 +1,13 @@
+{
+    "arch": "x64",
+    "description": "Widevine Content Decryption Module",
+    "manifest_version": 2,
+    "name": "WidevineCdm",
+    "os": "linux",
+    "version": "4.10.2209.1",
+    "x-cdm-codecs": "vp8,vp09,avc1,av01",
+    "x-cdm-host-versions": "10",
+    "x-cdm-interface-versions": "10",
+    "x-cdm-module-versions": "4",
+    "x-cdm-persistent-license-support": false
+}