Make the chrome.usb API available to Extensions.

extensions/common/api/_permission_features.json

Index: extensions/common/api/_permission_features.json
diff --git a/extensions/common/api/_permission_features.json b/extensions/common/api/_permission_features.json
index 736f0e3befebba01e1b51590017ae26081f8def7..073ee3a7b41575b6a1089187ce0f2854d3c93064 100644
--- a/extensions/common/api/_permission_features.json
+++ b/extensions/common/api/_permission_features.json
@@ -369,38 +369,14 @@
       "extension", "legacy_packaged_app", "hosted_app", "platform_app"
     ]
   },
-  "usb": [
-    {
-      "channel": "stable",
-      "extension_types": ["platform_app"]
-    },
-    {
-      "channel": "stable",
-      "extension_types": ["extension"],
-      "whitelist": [
-        "496B6890097EB6E19809ADEADD095A8721FBB2E0",  // FIDO U2F APIs
-        "AD8ED80B705E1818AAD4684F9FF62B43D6D79620",  // FIDO U2F APIs (dev)
-        "E24F1786D842E91E74C27929B0B3715A4689A473",  // CryptoToken
-        "A28C9619C4C41306FA5236FB4D94DA812F504DE8"   // CryptoToken (dev)
-      ]
-    }
-  ],
-  "usbDevices": [
-    {
-      "channel": "stable",
-      "extension_types": ["platform_app"]
-    },
-    {
-      "channel": "stable",
-      "extension_types": ["extension"],
-      "whitelist": [
-        "496B6890097EB6E19809ADEADD095A8721FBB2E0",  // FIDO U2F APIs
-        "AD8ED80B705E1818AAD4684F9FF62B43D6D79620",  // FIDO U2F APIs (dev)
-        "E24F1786D842E91E74C27929B0B3715A4689A473",  // CryptoToken
-        "A28C9619C4C41306FA5236FB4D94DA812F504DE8"   // CryptoToken (dev)
-      ]
-    }
-  ],
+  "usb": {
+    "channel": "stable",
+    "extension_types": ["extension", "platform_app"]
+  },
+  "usbDevices": {
+    "channel": "stable",
+    "extension_types": ["extension", "platform_app"]
+  },
   "videoCapture": [
     {
       "channel": "stable",