[Cleanup] Remove StringPrintf from global namespace

ash/magnifier/magnification_controller_unittest.cc

 // Copyright (c) 2013 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 "ash/display/display_controller.h"
 #include "ash/magnifier/magnification_controller.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "base/stringprintf.h"
 #include "ui/aura/client/aura_constants.h"
@@ skipping 10 matching lines @@
 
 }  // namespace
 
 class MagnificationControllerTest: public test::AshTestBase {
  public:
   MagnificationControllerTest() {}
   virtual ~MagnificationControllerTest() {}
 
   virtual void SetUp() OVERRIDE {
     AshTestBase::SetUp();
-    UpdateDisplay(StringPrintf("%dx%d", kRootWidth, kRootHeight));
+    UpdateDisplay(base::StringPrintf("%dx%d", kRootWidth, kRootHeight));
 
     aura::RootWindow* root = GetRootWindow();
     gfx::Rect root_bounds(root->bounds());
 
 #if defined(OS_WIN)
     // RootWindow and Display can't resize on Windows Ash.
     // http://crbug.com/165962
     EXPECT_EQ(kRootHeight, root_bounds.height());
     EXPECT_EQ(kRootWidth, root_bounds.width());
 #endif
@@ skipping 106 matching lines @@
 
   GetMagnificationController()->MoveWindow(200, 400, false);
   EXPECT_EQ("200,300 400x300", GetViewport().ToString());
 
   GetMagnificationController()->MoveWindow(1000, 1000, false);
   EXPECT_EQ("400,300 400x300", GetViewport().ToString());
 }
 
 }  // namespace internal
 }  // namespace ash