Adds UMA to measure when the data reduction proxy via header is missing

components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detection_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detection.h"
 
 #include <string.h>
 #include <algorithm>
 #include <map>
 #include <vector>
 
 #include "base/base64.h"
 #include "base/md5.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "components/data_reduction_proxy/common/data_reduction_proxy_headers.h"
+#include "components/data_reduction_proxy/common/data_reduction_proxy_headers_test_utils.h"
 #include "net/http/http_response_headers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/jni_android.h"
 #include "net/android/network_library.h"
 #endif
 
 namespace {
 
-void HeadersToRaw(std::string* headers) {
-  std::replace(headers->begin(), headers->end(), '\n', '\0');
-  if (!headers->empty())
-    *headers += '\0';
-}
-
 // Calcuates MD5 hash value for a string and then base64 encode it. Testcases
 // contain expected fingerprint in plain text, which needs to be encoded before
 // comparison.
 std::string GetEncoded(const std::string& input) {
   base::MD5Digest digest;
   base::MD5Sum(input.c_str(), input.size(), &digest);
   std::string base64encoded;
   base::Base64Encode(std::string((char*)digest.a,
                      ARRAYSIZE_UNSAFE(digest.a)), &base64encoded);
   return base64encoded;
@@ skipping 704 matching lines @@
         new net::HttpResponseHeaders(raw_headers));
 
     EXPECT_EQ(
         test[i].expected_tampered_with,
         DataReductionProxyTamperDetection::DetectAndReport(headers.get(), true))
         << test[i].label;
   }
 }
 
 } // namespace