Really fix build after r193020.

content/browser/tracing/tracing_ui.cc

Index: content/browser/tracing/tracing_ui.cc
diff --git a/content/browser/tracing/tracing_ui.cc b/content/browser/tracing/tracing_ui.cc
index 6c224c01f12b7acc20a22747aec5a37d4c9b1c77..40bbee3c15c7eb28b6f12cb6584105aab79464d1 100644
--- a/content/browser/tracing/tracing_ui.cc
+++ b/content/browser/tracing/tracing_ui.cc
@@ -319,7 +319,7 @@ void TracingMessageHandler::OnLoadTraceFile(const base::ListValue* list) {
       base::FilePath(),
       NULL,
       0,
-      FILE_PATH_LITERAL(std::string()),
+      base::FilePath::StringType(),
       web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
       NULL);
 }
@@ -372,7 +372,7 @@ void TracingMessageHandler::OnSaveTraceFile(const base::ListValue* list) {
       base::FilePath(),
       NULL,
       0,
-      FILE_PATH_LITERAL(std::string()),
+      base::FilePath::StringType(),
       web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
       NULL);
 }