Implement ui::ClipboardMus.

ui/views/mus/window_manager_connection.cc

Index: ui/views/mus/window_manager_connection.cc
diff --git a/ui/views/mus/window_manager_connection.cc b/ui/views/mus/window_manager_connection.cc
index f17c0aa96379af0e4f4211482041711d4505c760..80770cf04466a315c097c9a69d19a519a7f768bb 100644
--- a/ui/views/mus/window_manager_connection.cc
+++ b/ui/views/mus/window_manager_connection.cc
@@ -17,6 +17,7 @@
 #include "services/shell/public/cpp/connection.h"
 #include "services/shell/public/cpp/connector.h"
 #include "ui/events/devices/device_data_manager.h"
+#include "ui/views/mus/clipboard_mus.h"
 #include "ui/views/mus/native_widget_mus.h"
 #include "ui/views/mus/screen_mus.h"
 #include "ui/views/pointer_watcher.h"
@@ -114,6 +115,10 @@ WindowManagerConnection::WindowManagerConnection(
   screen_.reset(new ScreenMus(this));
   screen_->Init(connector);
 
+  std::unique_ptr<ClipboardMus> clipboard(new ClipboardMus);
+  clipboard->Init(connector);
+  ui::Clipboard::SetClipboardForCurrentThread(std::move(clipboard));
+
   if (!ui::DeviceDataManager::HasInstance()) {
     // TODO(sad): We should have a DeviceDataManager implementation that talks
     // to a mojo service to learn about the input-devices on the system.
@@ -132,6 +137,7 @@ WindowManagerConnection::~WindowManagerConnection() {
   // ~WindowTreeClient calls back to us (we're its delegate), destroy it while
   // we are still valid.
   client_.reset();
+  ui::Clipboard::DestroyClipboardForCurrentThread();
   if (created_device_data_manager_)
     ui::DeviceDataManager::DeleteInstance();