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

components/data_reduction_proxy/common/data_reduction_proxy_headers_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/common/data_reduction_proxy_headers.h"
 
 #include <vector>
 
+#include "components/data_reduction_proxy/common/data_reduction_proxy_headers_test_utils.h"
 #include "net/http/http_response_headers.h"
 #include "net/proxy/proxy_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace {
-
-// Transform "normal"-looking headers (\n-separated) to the appropriate
-// input format for ParseRawHeaders (\0-separated).
-void HeadersToRaw(std::string* headers) {
-  std::replace(headers->begin(), headers->end(), '\n', '\0');
-  if (!headers->empty())
-    *headers += '\0';
-}
-
-}  // namespace
-
 namespace data_reduction_proxy {
 
 class DataReductionProxyHeadersTest : public testing::Test {};
 
 TEST_F(DataReductionProxyHeadersTest, GetDataReductionProxyActionValue) {
   const struct {
      const char* headers;
      std::string action_key;
      bool expected_result;
      std::string expected_action_value;
@@ skipping 843 matching lines @@
     std::string output_values_string;
     for (size_t j = 0; j < output_values.size(); ++j)
       output_values_string += output_values[j] + ",";
 
     EXPECT_EQ(test[i].expected_output_values_string, output_values_string)
         << test[i].label;
   }
 }
 
 }  // namespace data_reduction_proxy