Move PathExists to base namespace.

chrome/test/base/v8_unit_test.cc

Index: chrome/test/base/v8_unit_test.cc
diff --git a/chrome/test/base/v8_unit_test.cc b/chrome/test/base/v8_unit_test.cc
index 1103a5cb3c51d0b5ab4d3207e6424adc70379018..b60502ccbb7e7e6da03a48f31f52057e7d8b1ffb 100644
--- a/chrome/test/base/v8_unit_test.cc
+++ b/chrome/test/base/v8_unit_test.cc
@@ -67,7 +67,7 @@ bool V8UnitTest::ExecuteJavascriptLibraries() {
     base::FilePath library_file(*user_libraries_iterator);
     if (!user_libraries_iterator->IsAbsolute()) {
       base::FilePath gen_file = gen_test_data_directory.Append(library_file);
-      library_file = file_util::PathExists(gen_file) ? gen_file :
+      library_file = base::PathExists(gen_file) ? gen_file :
           test_data_directory.Append(*user_libraries_iterator);
     }
     library_file = base::MakeAbsoluteFilePath(library_file);