Change other usages of .size() to .empty() when applicable.

chrome/browser/importer/firefox2_importer.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/importer/firefox2_importer.h"
 
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
@@ skipping 187 matching lines @@
                                         &post_data) ||
         ParseMinimumBookmarkFromLine(line, charset, &title, &url);
 
     if (is_bookmark)
       last_folder_is_empty = false;
 
     if (is_bookmark &&
         post_data.empty() &&
         CanImportURL(GURL(url)) &&
         default_urls.find(url) == default_urls.end()) {
-      if (toolbar_folder > path.size() && path.size() > 0) {
+      if (toolbar_folder > path.size() && !path.empty()) {
         NOTREACHED();  // error in parsing.
         break;
       }
 
       ProfileWriter::BookmarkEntry entry;
       entry.creation_time = add_date;
       entry.url = url;
       entry.title = title;
 
       if (import_to_bookmark_bar && toolbar_folder) {
@@ skipping 465 matching lines @@
 
   // We need to make up a URL for the favicon. We use a version of the page's
   // URL so that we can be sure it will not collide.
   usage.favicon_url = GURL(std::string("made-up-favicon:") + link_url.spec());
 
   // We only have one URL per favicon for Firefox 2 bookmarks.
   usage.urls.insert(link_url);
 
   favicons->push_back(usage);
 }