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

chrome/browser/ui/gtk/dialogs_gtk.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 <gtk/gtk.h>
 #include <map>
 #include <set>
 
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 281 matching lines @@
       gtk_file_filter_set_name(filter, mime_type.c_str());
     }
 
     gtk_file_chooser_add_filter(chooser, filter);
     if (i == file_type_index_ - 1)
       gtk_file_chooser_set_filter(chooser, filter);
   }
 
   // Add the *.* filter, but only if we have added other filters (otherwise it
   // is implied).
-  if (file_types_.include_all_files && file_types_.extensions.size() > 0) {
+  if (file_types_.include_all_files && !file_types_.extensions.empty()) {
     GtkFileFilter* filter = gtk_file_filter_new();
     gtk_file_filter_add_pattern(filter, "*");
     gtk_file_filter_set_name(filter,
         l10n_util::GetStringUTF8(IDS_SAVEAS_ALL_FILES).c_str());
     gtk_file_chooser_add_filter(chooser, filter);
   }
 }
 
 void SelectFileDialogImpl::FileSelected(GtkWidget* dialog,
                                         const FilePath& path) {
@@ skipping 268 matching lines @@
   GdkPixbuf* pixbuf = gdk_pixbuf_new_from_file_at_size(filename, kPreviewWidth,
                                                        kPreviewHeight, NULL);
   g_free(filename);
   if (pixbuf) {
     gtk_image_set_from_pixbuf(GTK_IMAGE(preview_), pixbuf);
     g_object_unref(pixbuf);
   }
   gtk_file_chooser_set_preview_widget_active(GTK_FILE_CHOOSER(chooser),
                                              pixbuf ? TRUE : FALSE);
 }