Revert of Implement ui::ClipboardMus.

components/mus/clipboard/clipboard_impl.cc

 // 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.
 
 #include "components/mus/clipboard/clipboard_impl.h"
 
 #include <string.h>
 #include <utility>
 
 #include "base/macros.h"
-#include "mojo/common/common_type_converters.h"
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/callback.h"
 #include "mojo/public/cpp/bindings/string.h"
 
 using mojo::Array;
 using mojo::Map;
 using mojo::String;
 
 namespace mus {
 namespace clipboard {
@@ skipping 56 matching lines @@
 }
 
 void ClipboardImpl::GetAvailableMimeTypes(
     Clipboard::Type clipboard_type,
     const GetAvailableMimeTypesCallback& callback) {
   int clipboard_num = static_cast<int>(clipboard_type);
   callback.Run(clipboard_state_[clipboard_num]->sequence_number(),
                clipboard_state_[clipboard_num]->GetMimeTypes());
 }
 
-void ClipboardImpl::ReadClipboardData(
+void ClipboardImpl::ReadMimeType(
+    uint64_t sequence,
     Clipboard::Type clipboard_type,
     const String& mime_type,
-    const ReadClipboardDataCallback& callback) {
+    const ReadMimeTypeCallback& callback) {
   int clipboard_num = static_cast<int>(clipboard_type);
   Array<uint8_t> mime_data(nullptr);
-  uint64_t sequence = clipboard_state_[clipboard_num]->sequence_number();
-  clipboard_state_[clipboard_num]->GetData(mime_type, &mime_data);
-  callback.Run(sequence, std::move(mime_data));
+  bool valid_sequence_number =
+      clipboard_state_[clipboard_num]->sequence_number() == sequence;
+
+  if (valid_sequence_number)
+    clipboard_state_[clipboard_num]->GetData(mime_type, &mime_data);
+
+  callback.Run(valid_sequence_number, std::move(mime_data));
 }
 
 void ClipboardImpl::WriteClipboardData(
     Clipboard::Type clipboard_type,
     Map<String, Array<uint8_t>> data,
     const WriteClipboardDataCallback& callback) {
   int clipboard_num = static_cast<int>(clipboard_type);
   clipboard_state_[clipboard_num]->SetData(std::move(data));
   callback.Run(clipboard_state_[clipboard_num]->sequence_number());
 }
 
 }  // namespace clipboard
 }  // namespace mus