Don't set MODE_DEFAULT when adding HPKP header.

chrome_frame/test/net/fake_external_tab.cc

Index: chrome_frame/test/net/fake_external_tab.cc
diff --git a/chrome_frame/test/net/fake_external_tab.cc b/chrome_frame/test/net/fake_external_tab.cc
index f5bbfba09fdffabed09490d5d98eae623dcfd5ff..c0653335c63aea04bee49f35d2b517467d54e952 100644
--- a/chrome_frame/test/net/fake_external_tab.cc
+++ b/chrome_frame/test/net/fake_external_tab.cc
@@ -254,10 +254,11 @@ void FilterDisabledTests() {
 
     // These tests use HTTPS, and IE's trust store does not have the test
     // certs. So these tests time out waiting for user input. The
-    // functionality they test (HTTP Strict Transport Security) does not
-    // work in Chrome Frame anyway.
+    // functionality they test (HTTP Strict Transport Security and
+    // HTTP-based Public Key Pinning) does not work in Chrome Frame anyway.
     "URLRequestTestHTTP.ProcessSTS",
     "URLRequestTestHTTP.ProcessSTSOnce",
+    "URLRequestTestHTTP.ProcessSTSAndPKP",
 
     // These tests have been disabled as the Chrome cookie policies don't make
     // sense or have not been implemented for the host network stack.