Move ReadFileToString to the base namespace.

content/common/sandbox_mac_fontloading_unittest.mm

Index: content/common/sandbox_mac_fontloading_unittest.mm
diff --git a/content/common/sandbox_mac_fontloading_unittest.mm b/content/common/sandbox_mac_fontloading_unittest.mm
index 57af4de8b743ee459f890ed7633a6568617ea01e..d78f2f4859e5dc60d1913a2f0c27e24e47bdf080 100644
--- a/content/common/sandbox_mac_fontloading_unittest.mm
+++ b/content/common/sandbox_mac_fontloading_unittest.mm
@@ -31,8 +31,7 @@ REGISTER_SANDBOX_TEST_CASE(FontLoadingTestCase);
 // Load raw font data into shared memory object.
 bool FontLoadingTestCase::BeforeSandboxInit() {
   std::string font_data;
-  if (!file_util::ReadFileToString(base::FilePath(test_data_.c_str()),
-                                   &font_data)) {
+  if (!base::ReadFileToString(base::FilePath(test_data_.c_str()), &font_data)) {
     LOG(ERROR) << "Failed to read font data from file (" << test_data_ << ")";
     return false;
   }