Add FilePath to base namespace.

chrome/browser/safe_browsing/signature_util.h

Index: chrome/browser/safe_browsing/signature_util.h
diff --git a/chrome/browser/safe_browsing/signature_util.h b/chrome/browser/safe_browsing/signature_util.h
index 2233a55cb806eed76a25f657ed5f1ef7f80cf6f1..00aef61e088a301c8ca79b42db61587380a0ce96 100644
--- a/chrome/browser/safe_browsing/signature_util.h
+++ b/chrome/browser/safe_browsing/signature_util.h
@@ -11,7 +11,9 @@
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 
+namespace base {
 class FilePath;
+}
 
 namespace safe_browsing {
 class ClientDownloadRequest_SignatureInfo;
@@ -23,7 +25,7 @@ class SignatureUtil : public base::RefCountedThreadSafe<SignatureUtil> {
   // Fills in the DownloadRequest_SignatureInfo for the given file path.
   // This method may be called on any thread.
   virtual void CheckSignature(
-      const FilePath& file_path,
+      const base::FilePath& file_path,
       ClientDownloadRequest_SignatureInfo* signature_info);
 
  protected: