WIP Enable WebUSB through the Experimental Framework.

third_party/WebKit/Source/modules/webusb/NavigatorUSB.idl

Index: third_party/WebKit/Source/modules/webusb/NavigatorUSB.idl
diff --git a/third_party/WebKit/Source/modules/webusb/NavigatorUSB.idl b/third_party/WebKit/Source/modules/webusb/NavigatorUSB.idl
index d916a0eab9e1efec91e0a6365fddb5099b9b0931..43c15da072ab2e8455fd2081198edd5c8b668503 100644
--- a/third_party/WebKit/Source/modules/webusb/NavigatorUSB.idl
+++ b/third_party/WebKit/Source/modules/webusb/NavigatorUSB.idl
@@ -6,7 +6,10 @@
 
 [
     GarbageCollected,
-    RuntimeEnabled=WebUSB,
+    //OriginTrialEnabled=WebUSB,
 ] partial interface Navigator {
-    readonly attribute USB usb;
+    // [OriginTrialEnabled] doesn't support adding bindings to partial
+    // interfaces yet, so we add it to the attribute instead.
+    // https://crbug.com/585656
+    [OriginTrialEnabled=WebUSB] readonly attribute USB usb;
 };