Move geometry interface files to geometry directory.

third_party/WebKit/Source/core/geometry/DOMRect.idl

 // Copyright 2014 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://dev.w3.org/fxtf/geometry/#DOMRect
 
 [
     Constructor(optional unrestricted double x = 0,
                 optional unrestricted double y = 0,
                 optional unrestricted double width = 0,
                 optional unrestricted double height = 0),
     Exposed=(Window,Worker),
     RuntimeEnabled=GeometryInterfaces,
 ] interface DOMRect : DOMRectReadOnly {
     [NewObject] static DOMRect fromRect(optional DOMRectInit other);
 
     inherit attribute unrestricted double x;
     inherit attribute unrestricted double y;
     inherit attribute unrestricted double width;
     inherit attribute unrestricted double height;
 };