Replace TestHeadersHandler::OnHeaderBlockEnd body with call to other method.

This CL lands part of server change 153489255.

BUG=488484

Review-Url: https://codereview.chromium.org/2829463002
Cr-Commit-Position: refs/heads/master@{#465727}

net/spdy/spdy_test_utils.cc

@@ -152,8 +152,7 @@ void TestHeadersHandler::OnHeader(SpdyStringPiece name, SpdyStringPiece value) {
 }
 
 void TestHeadersHandler::OnHeaderBlockEnd(size_t header_bytes_parsed) {
-  header_bytes_parsed_ = header_bytes_parsed;
-  compressed_header_bytes_parsed_ = 0;
+  OnHeaderBlockEnd(header_bytes_parsed, 0);
 }
 
 void TestHeadersHandler::OnHeaderBlockEnd(