Add explicit base to FilePath.

content/test/test_content_browser_client.cc

Index: content/test/test_content_browser_client.cc
diff --git a/content/test/test_content_browser_client.cc b/content/test/test_content_browser_client.cc
index de7be0636351ec68e11a94973f5e11083e7d7e31..c1c054b7e1b29195e1e05237643f2f5dc266e253 100644
--- a/content/test/test_content_browser_client.cc
+++ b/content/test/test_content_browser_client.cc
@@ -31,7 +31,7 @@ WebContentsView* TestContentBrowserClient::OverrideCreateWebContentsView(
 #endif
 }
 
-FilePath TestContentBrowserClient::GetDefaultDownloadDirectory() {
+base::FilePath TestContentBrowserClient::GetDefaultDownloadDirectory() {
   if (!download_dir_.IsValid()) {
     bool result = download_dir_.CreateUniqueTempDir();
     CHECK(result);