linux_aura: Implement dropping in chrome.

ui/base/x/selection_requestor.h

 // Copyright (c) 2013 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_BASE_X_SELECTION_REQUESTOR_H_
 #define UI_BASE_X_SELECTION_REQUESTOR_H_
 
 #include <X11/Xlib.h>
 
 // Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
 #undef RootWindow
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "ui/base/ui_export.h"
 #include "ui/base/x/x11_atom_cache.h"
 
 namespace ui {
+class SelectionData;
 
 // Requests and later receives data from the X11 server through the selection
 // system.
 //
 // X11 uses a system called "selections" to implement clipboards and drag and
 // drop. This class interprets messages from the statefull selection request
 // API. SelectionRequestor should only deal with the X11 details; it does not
 // implement per-component fast-paths.
 class UI_EXPORT SelectionRequestor {
  public:
   SelectionRequestor(Display* xdisplay,
                      ::Window xwindow,
                      ::Atom selection_name);
   ~SelectionRequestor();
 
   // Does the work of requesting |target| from the selection we handle,
   // spinning up the nested message loop, and reading the resulting data
   // back. |out_data| is allocated with the X allocator and must be freed with
   // XFree(). |out_data_bytes| is the length in machine chars, while
   // |out_data_items| is the length in |out_type| items.
   bool PerformBlockingConvertSelection(::Atom target,
                                        unsigned char** out_data,
                                        size_t* out_data_bytes,
                                        size_t* out_data_items,
                                        ::Atom* out_type);
 
+  // Returns the first of |types| offered by the current selection holder, or
+  // returns NULL if none of those types are available.
+  scoped_ptr<SelectionData> RequestAndWaitForTypes(
+      const std::vector< ::Atom>& types);
+
   // It is our owner's responsibility to plumb X11 SelectionNotify events on
   // |xwindow_| to us.
   void OnSelectionNotify(const XSelectionEvent& event);
 
  private:
   // Our X11 state.
   Display* x_display_;
   ::Window x_window_;
 
   // True if we're currently running a nested message loop, waiting for data to
@@ skipping 17 matching lines @@
   base::Closure quit_closure_;
 
   X11AtomCache atom_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectionRequestor);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_SELECTION_REQUESTOR_H_