Move ReadFileToString to the base namespace.

net/proxy/proxy_resolver_v8_tracing_unittest.cc

Index: net/proxy/proxy_resolver_v8_tracing_unittest.cc
diff --git a/net/proxy/proxy_resolver_v8_tracing_unittest.cc b/net/proxy/proxy_resolver_v8_tracing_unittest.cc
index ff3ffd4a27a553aac6094989d4eb76b5ecc7e8eb..805a87343652253aabee677e7659635471ed0eca 100644
--- a/net/proxy/proxy_resolver_v8_tracing_unittest.cc
+++ b/net/proxy/proxy_resolver_v8_tracing_unittest.cc
@@ -49,7 +49,7 @@ scoped_refptr<ProxyResolverScriptData> LoadScriptData(const char* filename) {
 
   // Try to read the file from disk.
   std::string file_contents;
-  bool ok = file_util::ReadFileToString(path, &file_contents);
+  bool ok = base::ReadFileToString(path, &file_contents);
 
   // If we can't load the file from disk, something is misconfigured.
   EXPECT_TRUE(ok) << "Failed to read file: " << path.value();