[InputEvent] Introduce |StaticRange| and use in |InputEvent::getRanges()|

third_party/WebKit/Source/core/dom/StaticRange.idl

+// Copyright 2016 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.
+
+// https://discourse.wicg.io/t/proposal-staticrange-to-be-used-instead-of-range-for-new-apis/1472
+
+[
+    Constructor,
+    Exposed=Window,
+    RuntimeEnabled=InputEvent,
+] interface StaticRange {
+    attribute Node startContainer;
+    attribute long startOffset;
+    attribute Node endContainer;
+    attribute long endOffset;
+    readonly attribute boolean collapsed;
+
+    void setStart(Node node, long offset);
+    void setEnd(Node node, long offset);
+
+    [NewObject, RaisesException, CallWith=ScriptState] Range toRange();
+};