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

chrome/browser/plugin_exceptions_table_model_unittest.cc

 // 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.
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/mock_plugin_exceptions_table_model.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/testing_pref_service.h"
@@ skipping 119 matching lines @@
       } else {
         // Plugin IDs are ascending one by one.
         EXPECT_EQ(last_plugin+1, it->plugin_id);
 
         // Consecutive runs of plugins with id |x| are |row_counts[x]| long.
         EXPECT_EQ(count, row_counts[last_plugin]);
         count = 1;
         last_plugin = it->plugin_id;
       }
     }
-    if (row_counts.size() > 0)
+    if (!row_counts.empty())
       EXPECT_EQ(count, row_counts[last_plugin]);
   }
 
  protected:
   MessageLoop message_loop_;
   BrowserThread ui_thread_;
 
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<MockPluginExceptionsTableModel> table_model_;
 
@@ skipping 58 matching lines @@
   plugin_test_internal::MockTableModelObserver observer(table_model_.get());
   table_model_->SetObserver(&observer);
 
   EXPECT_CALL(observer, OnModelChanged());
   table_model_->RemoveAll();
   EXPECT_EQ(0, table_model_->RowCount());
   EXPECT_EQ(0, static_cast<int>(table_model_->GetGroups().size()));
   CheckInvariants();
   table_model_->SetObserver(NULL);
 }