Move ReadFileToString to the base namespace.

webkit/support/test_webkit_platform_support.cc

Index: webkit/support/test_webkit_platform_support.cc
diff --git a/webkit/support/test_webkit_platform_support.cc b/webkit/support/test_webkit_platform_support.cc
index 276a10e77bcd3fd00209d02c02e9e16eeb774575..ae0a7e583097c5318c1a4bc1a7a3f093d68116f7 100644
--- a/webkit/support/test_webkit_platform_support.cc
+++ b/webkit/support/test_webkit_platform_support.cc
@@ -314,7 +314,7 @@ WebKit::WebData TestWebKitPlatformSupport::readFromFile(
   base::FilePath file_path = base::FilePath::FromUTF16Unsafe(path);
 
   std::string buffer;
-  file_util::ReadFileToString(file_path, &buffer);
+  base::ReadFileToString(file_path, &buffer);
 
   return WebKit::WebData(buffer.data(), buffer.size());
 }