Add WebUSB bindings and client interface

Source/modules/webusb/USB.h

Index: Source/modules/webusb/USB.h
diff --git a/Source/modules/webusb/USB.h b/Source/modules/webusb/USB.h
new file mode 100644
index 0000000000000000000000000000000000000000..3e7fc31d667087b9123e5fd58c92eaf520e7005b
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+++ b/Source/modules/webusb/USB.h
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+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef USB_h
+#define USB_h
+
+#include "bindings/core/v8/ScriptPromise.h"
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "modules/webusb/USBController.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class LocalFrame;
+class ScriptState;
+class USBDeviceEnumerationOptions;
+
+class USB final
+    : public GarbageCollectedFinalized<USB>
+    , public ScriptWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static USB* create(LocalFrame& frame)
+    {
+        return new USB(frame);
+    }
+
+    USB(LocalFrame& frame);
+
+    ScriptPromise getDevices(ScriptState*, const USBDeviceEnumerationOptions&);
+
+    DECLARE_VIRTUAL_TRACE();
+
+private:
+    RawPtrWillBeMember<USBController> m_controller;
+};
+
+} // namespace blink
+
+#endif // USB_h