Implement ui::ClipboardMus.

ui/views/mus/aura_init.cc

Index: ui/views/mus/aura_init.cc
diff --git a/ui/views/mus/aura_init.cc b/ui/views/mus/aura_init.cc
index 5335188700b22c2e8aa2cab998472ff8e0f439c1..c04b070a731b0fb063f342212d8950a21c79a9b9 100644
--- a/ui/views/mus/aura_init.cc
+++ b/ui/views/mus/aura_init.cc
@@ -17,6 +17,7 @@
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
+#include "ui/views/mus/clipboard_mus.h"
 #include "ui/views/views_delegate.h"
 
 #if defined(OS_LINUX) && !defined(OS_ANDROID)
@@ -59,6 +60,10 @@ AuraInit::AuraInit(shell::Connector* connector,
   ui::MaterialDesignController::Initialize();
   InitializeResources(connector);
 
+  std::unique_ptr<ClipboardMus> clipboard(new ClipboardMus);
+  clipboard->Init(connector);
+  ui::Clipboard::SetClipboardForCurrentThread(std::move(clipboard));
+
   ui::InitializeInputMethodForTesting();
 }