Add FilePath to base namespace.

webkit/plugins/npapi/plugin_instance.cc

Index: webkit/plugins/npapi/plugin_instance.cc
diff --git a/webkit/plugins/npapi/plugin_instance.cc b/webkit/plugins/npapi/plugin_instance.cc
index f26cbec67e55abfe8d767c60e63039af1b727a7c..4d49a05dc378a7541a27b80e3b3f36ec0620818a 100644
--- a/webkit/plugins/npapi/plugin_instance.cc
+++ b/webkit/plugins/npapi/plugin_instance.cc
@@ -315,7 +315,7 @@ void PluginInstance::NPP_StreamAsFile(NPStream *stream, const char *fname) {
   // Creating a temporary FilePath instance on the stack as the explicit
   // FilePath constructor with StringType as an argument causes a compiler
   // error when invoked via vector push back.
-  FilePath file_name = FilePath::FromWStringHack(UTF8ToWide(fname));
+  base::FilePath file_name = base::FilePath::FromWStringHack(UTF8ToWide(fname));
   files_created_.push_back(file_name);
 }