linux_aura: Don't clear target vector in SelectionOwner.

ui/base/x/selection_owner.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_OWNER_H_
 #define UI_BASE_X_SELECTION_OWNER_H_
 
 #include <X11/Xlib.h>
 
 // Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
@@ skipping 17 matching lines @@
 class UI_BASE_EXPORT SelectionOwner {
  public:
   SelectionOwner(Display* xdisplay,
                  ::Window xwindow,
                  ::Atom selection_name);
   ~SelectionOwner();
 
   // Returns the current selection data. Useful for fast paths.
   const SelectionFormatMap& selection_format_map() { return format_map_; }
 
-  // Retrieves a list of types we're offering.
+  // Appends a list of types we're offering to |targets|.
   void RetrieveTargets(std::vector<Atom>* targets);
 
   // Attempts to take ownership of the selection. If we're successful, present
   // |data| to other windows.
   void TakeOwnershipOfSelection(const SelectionFormatMap& data);
 
   // Releases the selection (if we own it) and clears any data we own.
   void Clear();
 
   // It is our owner's responsibility to plumb X11 events on |xwindow_| to us.
@@ skipping 14 matching lines @@
   SelectionFormatMap format_map_;
 
   X11AtomCache atom_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectionOwner);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_SELECTION_OWNER_H_