Adds cache lock timeout handling after finishing headers phase.

net/http/mock_http_cache.cc

Index: net/http/mock_http_cache.cc
diff --git a/net/http/mock_http_cache.cc b/net/http/mock_http_cache.cc
index e676122b53f4c77492d3676dac08bf517b0220dd..9f614362ced6737d14949ff4f7264b2a79206649 100644
--- a/net/http/mock_http_cache.cc
+++ b/net/http/mock_http_cache.cc
@@ -589,6 +589,10 @@ void MockHttpCache::SimulateCacheLockTimeout() {
   http_cache_.SimulateCacheLockTimeout();
 }
 
+void MockHttpCache::SimulateCacheLockTimeoutAfterHeaders() {
+  http_cache_.SimulateCacheLockTimeoutAfterHeaders();
+}
+
 void MockHttpCache::FailConditionalizations() {
   http_cache_.FailConditionalizationForTest();
 }