Add FilePath to base namespace.

base/perftimer.h

Index: base/perftimer.h
diff --git a/base/perftimer.h b/base/perftimer.h
index 1ac1a7d18901e268cfe02585322b68b0aafc3c03..9a23ff1d6fe5a35dddf02484aa98bd9d710b9b99 100644
--- a/base/perftimer.h
+++ b/base/perftimer.h
@@ -10,14 +10,16 @@
 #include "base/basictypes.h"
 #include "base/time.h"
 
+namespace base {
 class FilePath;
+}
 
 // ----------------------------------------------------------------------
 // Initializes and finalizes the perf log. These functions should be
 // called at the beginning and end (respectively) of running all the
 // performance tests. The init function returns true on success.
 // ----------------------------------------------------------------------
-bool InitPerfLog(const FilePath& log_path);
+bool InitPerfLog(const base::FilePath& log_path);
 void FinalizePerfLog();
 
 // ----------------------------------------------------------------------