base: Get rid of 'using' declaration of StringAppendF.

chrome/test/startup/feature_startup_test.cc

 // Copyright (c) 2006-2008 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/file_util.h"
 #include "base/path_service.h"
 #include "base/perftimer.h"
 #include "base/string_util.h"
 #include "base/time.h"
 #include "chrome/app/chrome_command_ids.h"
@@ skipping 17 matching lines @@
 
   void SetUp() {}
   void TearDown() {}
 
   static const int kNumCycles = 5;
 
   void PrintTimings(const char* label, TimeDelta timings[kNumCycles],
                     bool important) {
     std::string times;
     for (int i = 0; i < kNumCycles; ++i)
-      StringAppendF(&times, "%.2f,", timings[i].InMillisecondsF());
+      base::StringAppendF(&times, "%.2f,", timings[i].InMillisecondsF());
     PrintResultList("new_tab", "", label, times, "ms", important);
   }
 
   void InitProfile(UITest::ProfileType profile_type) {
     profile_type_ = profile_type;
 
     // Install the location of the test profile file.
     set_template_user_data(UITest::ComputeTypicalUserDataSource(
         profile_type));
 
@@ skipping 157 matching lines @@
 }
 
 TEST_F(NewTabUIStartupTest, NativeFrameGtkThemeCold) {
   RunStartupTest("tab_custom_frame_gtk_theme_cold", false /* cold */,
                  false /* not important */,
                  UITest::CUSTOM_FRAME_NATIVE_THEME);
 }
 #endif
 
 }  // namespace