Move ReadFileToString to the base namespace.

cc/trees/layer_tree_host_perftest.cc

 // Copyright 2012 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 "cc/trees/layer_tree_host.h"
 
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "base/strings/string_piece.h"
@@ skipping 97 matching lines @@
  public:
   LayerTreeHostPerfTestJsonReader()
       : LayerTreeHostPerfTest() {
   }
 
   void ReadTestFile(std::string name) {
     test_name_ = name;
     base::FilePath test_data_dir;
     ASSERT_TRUE(PathService::Get(cc::DIR_TEST_DATA, &test_data_dir));
     base::FilePath json_file = test_data_dir.AppendASCII(name + ".json");
-    ASSERT_TRUE(file_util::ReadFileToString(json_file, &json_));
+    ASSERT_TRUE(base::ReadFileToString(json_file, &json_));
   }
 
   virtual void BuildTree() OVERRIDE {
     gfx::Size viewport = gfx::Size(720, 1038);
     layer_tree_host()->SetViewportSize(viewport);
     scoped_refptr<Layer> root = ParseTreeFromJson(json_,
                                                   &fake_content_layer_client_);
     ASSERT_TRUE(root.get());
     layer_tree_host()->SetRootLayer(root);
   }
@@ skipping 148 matching lines @@
 };
 
 TEST_F(PageScaleImplSidePaintingPerfTest, HeavyPage) {
   measure_commit_cost_ = true;
   ReadTestFile("heavy_layer_tree");
   RunTestWithImplSidePainting();
 }
 
 }  // namespace
 }  // namespace cc