mus: Remove window server access to clipboard and the drag clipboard.

services/ui/public/interfaces/clipboard.mojom

 // 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.
 
 module ui.mojom;
 
 const string kMimeTypeHTML = "text/html";
 const string kMimeTypeMozillaURL = "text/x-moz-url";
 const string kMimeTypePNG = "image/png";
 const string kMimeTypeRTF = "text/rtf";
 const string kMimeTypeText = "text/plain";
 const string kMimeTypeURIList = "text/uri-list";
 const string kMimeTypeURL = "text/url";
 
 interface Clipboard {
   enum Type {
     COPY_PASTE = 0,
-    SELECTION = 1,
-    DRAG = 2
+    SELECTION = 1
   };
 
   // Returns a sequence number which uniquely identifies clipboard state.
   // Clients are able to assume that the clipboard contents are unchanged as
   // long as this number has not changed. This number is monotonically
   // increasing, is increased when the clipboard state changes, and is
   // provided by Windows, Linux, and Mac.
   [Sync]
   GetSequenceNumber(Type clipboard_type) => (uint64 sequence);
 
@@ skipping 11 matching lines @@
   ReadClipboardData(Type clipboard_type, string mime_type)
       => (uint64 sequence, array<uint8>? data);
 
   // Writes a set of mime types to the clipboard. This will increment the
   // sequence number and return that. In the case of an empty or null map,
   // this will just clear the clipboard.
   [Sync]
   WriteClipboardData(Type clipboard_type, map<string, array<uint8>>? data)
       => (uint64 sequence);
 };