Use FilePaths in content::DropData to avoid redundant conversions.

ui/base/ui_base.gyp

 # Copyright 2014 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 142 matching lines @@
         'dragdrop/drag_source_win.cc',
         'dragdrop/drag_source_win.h',
         'dragdrop/drag_utils.cc',
         'dragdrop/drag_utils.h',
         'dragdrop/drag_utils_aura.cc',
         'dragdrop/drag_utils_win.cc',
         'dragdrop/drop_target_event.cc',
         'dragdrop/drop_target_event.h',
         'dragdrop/drop_target_win.cc',
         'dragdrop/drop_target_win.h',
+        'dragdrop/file_info.cc',
+        'dragdrop/file_info.h',
         'dragdrop/gtk_dnd_util.cc',
         'dragdrop/gtk_dnd_util.h',
         'dragdrop/os_exchange_data.cc',
         'dragdrop/os_exchange_data.h',
         'dragdrop/os_exchange_data_provider_aura.cc',
         'dragdrop/os_exchange_data_provider_aura.h',
         'dragdrop/os_exchange_data_provider_aurax11.cc',
         'dragdrop/os_exchange_data_provider_aurax11.h',
         'dragdrop/os_exchange_data_provider_win.cc',
         'dragdrop/os_exchange_data_provider_win.h',
@@ skipping 448 matching lines @@
            'variables': {
              'jni_gen_package': 'ui',
              'jni_generator_ptr_type': 'long',
            },
            'includes': [ '../../build/jni_generator.gypi' ],
          },
        ],
     }],
   ],
 }