Move WebDropData to content::DropData and split off conversion function.

content/content_common.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../components/tracing.gyp:tracing',
     '../media/media.gyp:media',
     '../net/net.gyp:net',
@@ skipping 20 matching lines @@
     'public/common/content_constants.h',
     'public/common/content_descriptors.h',
     'public/common/content_ipc_logging.h',
     'public/common/content_paths.h',
     'public/common/content_restriction.h',
     'public/common/content_switches.cc',
     'public/common/content_switches.h',
     'public/common/context_menu_params.cc',
     'public/common/context_menu_params.h',
     'public/common/console_message_level.h',
+    'public/common/drop_data.cc',
+    'public/common/drop_data.h',
     'public/common/favicon_url.cc',
     'public/common/favicon_url.h',
     'public/common/file_chooser_params.cc',
     'public/common/file_chooser_params.h',
     'public/common/frame_navigate_params.cc',
     'public/common/frame_navigate_params.h',
     'public/common/geoposition.cc',
     'public/common/geoposition.h',
     'public/common/gpu_memory_stats.cc',
     'public/common/gpu_memory_stats.h',
@@ skipping 487 matching lines @@
         '..\\third_party\\directxsdk\\files\\Redist\\<(input)',
         '<(output)',
         '<(PRODUCT_DIR)',
         ],
         'msvs_cygwin_shell': 1,
       },
      ]
     }],
   ],
 }