Migrate WebUSB LayoutTests into external/wpt

third_party/WebKit/LayoutTests/external/wpt/webusb/resources/usb-helpers.js

Index: third_party/WebKit/LayoutTests/external/wpt/webusb/resources/usb-helpers.js
diff --git a/third_party/WebKit/LayoutTests/usb/resources/usb-helpers.js b/third_party/WebKit/LayoutTests/external/wpt/webusb/resources/usb-helpers.js
similarity index 82%
rename from third_party/WebKit/LayoutTests/usb/resources/usb-helpers.js
rename to third_party/WebKit/LayoutTests/external/wpt/webusb/resources/usb-helpers.js
index 22e5a65d657b25440d6e1a14645d1cf05a06097f..454f9090d2ce884417d410aa6b87be9c462f1e93 100644
--- a/third_party/WebKit/LayoutTests/usb/resources/usb-helpers.js
+++ b/third_party/WebKit/LayoutTests/external/wpt/webusb/resources/usb-helpers.js
@@ -74,24 +74,17 @@ function assertDeviceInfoEquals(usbDevice, deviceInit) {
   }
 }
 
-// TODO(reillyg): Remove when jyasskin upstreams this to testharness.js:
-// https://crbug.com/509058.
-function callWithKeyDown(functionCalledOnKeyPress) {
+function callWithTrustedClick(callback) {
   return new Promise(resolve => {
-    function onKeyPress() {
-      document.removeEventListener('keypress', onKeyPress, false);
-      resolve(functionCalledOnKeyPress());
-    }
-    document.addEventListener('keypress', onKeyPress, false);
-
-    eventSender.keyDown(' ', []);
-  });
-}
-
-function runGarbageCollection() {
-  // Run gc() as a promise.
-  return new Promise((resolve, reject) => {
-    GCController.collect();
-    setTimeout(resolve, 0);
+    let button = document.createElement('button');
+    button.textContent = 'click to continue test';
+    button.style.display = 'block';
+    button.style.fontSize = '20px';
+    button.style.padding = '10px';
+    button.onclick = () => {
+      resolve(callback());
+      document.body.removeChild(button);
+    };
+    document.body.appendChild(button);
   });
 }