Revert of Implement ui::ClipboardMus.

components/mus/clipboard/clipboard_impl.cc

Index: components/mus/clipboard/clipboard_impl.cc
diff --git a/components/mus/clipboard/clipboard_impl.cc b/components/mus/clipboard/clipboard_impl.cc
index 221359f963511fb6c2fc96e5352cc450582b8332..0a66431592ab5d8810c2b39ad69e918e0b899c61 100644
--- a/components/mus/clipboard/clipboard_impl.cc
+++ b/components/mus/clipboard/clipboard_impl.cc
@@ -8,7 +8,6 @@
 #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"
@@ -85,15 +84,20 @@
                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(