Add FilePath to base namespace.

chrome/browser/prefs/pref_service_builder.h

Index: chrome/browser/prefs/pref_service_builder.h
diff --git a/chrome/browser/prefs/pref_service_builder.h b/chrome/browser/prefs/pref_service_builder.h
index adcbdf06070b36a3f7c49863a2b6af9eef521f0c..208e334feff02438b5ac5e5bdfeddba1b3ec789c 100644
--- a/chrome/browser/prefs/pref_service_builder.h
+++ b/chrome/browser/prefs/pref_service_builder.h
@@ -11,10 +11,10 @@
 #include "base/prefs/persistent_pref_store.h"
 #include "base/prefs/pref_store.h"
 
-class FilePath;
 class PrefServiceSimple;
 
 namespace base {
+class FilePath;
 class SequencedTaskRunner;
 }
 
@@ -40,7 +40,7 @@ class PrefServiceBuilder {
 
   // Specifies to use an actual file-backed user pref store.
   PrefServiceBuilder& WithUserFilePrefs(
-      const FilePath& prefs_file,
+      const base::FilePath& prefs_file,
       base::SequencedTaskRunner* task_runner);
 
   PrefServiceBuilder& WithAsync(bool async);