Add FilePath to base namespace.

content/browser/download/file_metadata_linux.h

Index: content/browser/download/file_metadata_linux.h
diff --git a/content/browser/download/file_metadata_linux.h b/content/browser/download/file_metadata_linux.h
index 5494add1f9b4bd360d1c46d6b8902635f9ff5bf7..c4fc3045c41f24d13286b2c498879c2fa6693796 100644
--- a/content/browser/download/file_metadata_linux.h
+++ b/content/browser/download/file_metadata_linux.h
@@ -7,9 +7,12 @@
 
 #include "content/common/content_export.h"
 
-class FilePath;
 class GURL;
 
+namespace base {
+class FilePath;
+}
+
 namespace content {
 
 // The source URL attribute is part of the XDG standard.
@@ -22,7 +25,7 @@ CONTENT_EXPORT extern const char kReferrerURLAttrName[];
 // Adds origin metadata to the file.
 // |source| should be the source URL for the download, and |referrer| should be
 // the URL the user initiated the download from.
-CONTENT_EXPORT void AddOriginMetadataToFile(const FilePath& file,
+CONTENT_EXPORT void AddOriginMetadataToFile(const base::FilePath& file,
                                             const GURL& source,
                                             const GURL& referrer);