mash: Use the new mus drag and drop API to get drag working in mash.

ui/views/mus/os_exchange_data_provider_mus.h

 // 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.
 
 #ifndef UI_VIEWS_MUS_OS_EXCHANGE_DATA_PROVIDER_MUS_H_
 #define UI_VIEWS_MUS_OS_EXCHANGE_DATA_PROVIDER_MUS_H_
 
 #include "ui/base/dragdrop/os_exchange_data.h"
 
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
 #include "mojo/public/cpp/bindings/map.h"
 #include "ui/gfx/geometry/vector2d.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/mus/mus_export.h"
 
 namespace views {
 
 // Translates chrome's requests for various data types to a platform specific
 // type. In the case of mus, this is a mapping of MIME types to byte arrays.
 //
 // TODO(erg): In the long run, there's a lot of optimizations that we can do
 // once everything targets mus. The entire model of OSExchangeDataProvider
 // shoves all data across the wire at once whether it is needed or not.
 class VIEWS_MUS_EXPORT OSExchangeDataProviderMus
     : public ui::OSExchangeData::Provider {
  public:
   using Data = std::map<std::string, std::vector<uint8_t>>;
 
   OSExchangeDataProviderMus();
+  explicit OSExchangeDataProviderMus(Data data);
   ~OSExchangeDataProviderMus() override;
 
   // Returns the raw MIME type to data mapping.
   Data GetData() const;
 
   // Overridden from OSExchangeData::Provider:
   std::unique_ptr<Provider> Clone() const override;
 
   void MarkOriginatedFromRenderer() override;
   bool DidOriginateFromRenderer() const override;
@@ skipping 63 matching lines @@
   gfx::Vector2d drag_image_offset_;
 
   Data mime_data_;
 
   DISALLOW_COPY_AND_ASSIGN(OSExchangeDataProviderMus);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_MUS_OS_EXCHANGE_DATA_PROVIDER_MUS_H_