Don't populate URL data in WebDropData when dragging files.

This is considered a potential security issue as well, since it leaks
filesystem paths.

BUG=332579

Review URL: https://codereview.chromium.org/135633002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244538 0039d316-1c4b-4281-b951-d872f2087c98
bool OSExchangeDataProviderWin::GetURLAndTitle(GURL* url,
bool OSExchangeDataProviderWin::GetURLAndTitle(
    OSExchangeData::FilenameToURLPolicy policy,
    GURL* url,
    base::string16* title) const {
   base::string16 url_str;
  bool success = ClipboardUtil::GetUrl(
      source_object_,
      &url_str,
      title,
      policy == OSExchangeData::CONVERT_FILENAMES ? true : false);
   if (success) {
     GURL test_url(url_str);
     if (test_url.is_valid()) {
      *url = test_url;
      return true;
    }
  } else if (GetPlainTextURL(source_object_, url)) {
    if (url->is_valid())
      *title = net::GetSuggestedFilename(*url, "", "", "", "", std::string());
    else
      title->clear();
    return true;
  }
  return false;
}

bool OSExchangeDataProviderWin::GetURLAndTitle(GURL* url,
                                               base::string16* title) const {
   base::string16 url_str;
  bool success = ClipboardUtil::GetUrl(source_object_, &url_str, title, true);
   if (success) {
     GURL test_url(url_str);
     if (test_url.is_valid()) {
      *url = test_url;
      return true;
    }
  } else if (GetPlainTextURL(source_object_, url)) {
    if (url->is_valid())
      *title = net::GetSuggestedFilename(*url, "", "", "", "", std::string());
    else
      title->clear();
    return true;
  }
  return false;
}
