Pure pedantry: Replace all ".size() == 0" with ".empty()".

chrome/browser/ui/cocoa/bookmarks/bookmark_editor_controller_unittest.mm

 // Copyright (c) 2010 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/string16.h"
 #include "base/sys_string_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
@@ skipping 270 matching lines @@
 
   // After changing a node, pointers to the node may be invalid.  This
   // is because the node itself may not be updated; it may removed and
   // a new one is added in that location.  (Implementation detail of
   // BookmarkEditorController).  This method updates the class's
   // bookmark_bb_3_ so that it points to the new node for testing.
   void UpdateBB3() {
     std::vector<const BookmarkNode*> nodes;
     BookmarkModel* model = browser_helper_.profile()->GetBookmarkModel();
     model->GetNodesByURL(bb3_url_1_, &nodes);
-    if (nodes.size() == 0)
+    if (nodes.empty())
       model->GetNodesByURL(bb3_url_2_, &nodes);
     DCHECK(nodes.size());
     bookmark_bb_3_ = nodes[0];
   }
 
 };
 
 TEST_F(BookmarkEditorControllerTreeTest, VerifyBookmarkTestModel) {
   BookmarkModel& model(*(browser_helper_.profile()->GetBookmarkModel()));
   model.root_node();
@@ skipping 112 matching lines @@
 
 TEST_F(BookmarkEditorControllerTreeNoNodeTest, NewBookmarkNoNode) {
   [controller_ setDisplayName:@"NEW BOOKMARK"];
   [controller_ setDisplayURL:@"http://NEWURL.com"];
   [controller_ ok:nil];
   const BookmarkNode* new_node = group_bb_->GetChild(5);
   ASSERT_EQ(0, new_node->GetChildCount());
   EXPECT_EQ(new_node->GetTitle(), ASCIIToUTF16("NEW BOOKMARK"));
   EXPECT_EQ(new_node->GetURL(), GURL("http://NEWURL.com"));
 }