Use text/plain as a test MIME type instead of application/pdf.

net/base/net_util_unittest.cc

Index: net/base/net_util_unittest.cc
diff --git a/net/base/net_util_unittest.cc b/net/base/net_util_unittest.cc
index e971573568daae33de9dd5a86f4b8001cdffc986..5a24a315d58e7c9627bc71b5e7ff7406f28b4b74 100644
--- a/net/base/net_util_unittest.cc
+++ b/net/base/net_util_unittest.cc
@@ -2289,16 +2289,16 @@ TEST(NetUtilTest, GenerateFileName) {
       "",
       "",
       "",
-      "application/pdf",
+      "text/plain",
       L"download",
-      L"npdf.pdf"
+      L"npdf" TXT_EXT
     },
     { // Shouldn't overwrite C-D specified extension.
       "http://www.example.com/npdf.php?fn=foobar.pdf",
       "Content-Disposition: filename=foobar.jpg",
       "",
       "",
-      "application/pdf",
+      "text/plain",
       L"download",
       L"foobar.jpg"
     },