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

components/data_reduction_proxy/browser/data_reduction_proxy_protocol_unittest.cc

Index: components/data_reduction_proxy/browser/data_reduction_proxy_protocol_unittest.cc
diff --git a/components/data_reduction_proxy/browser/data_reduction_proxy_protocol_unittest.cc b/components/data_reduction_proxy/browser/data_reduction_proxy_protocol_unittest.cc
index c4c13ee5bc8922a5f7218a728614e476e6707d26..d54aa86be3dca6bd8b2266e6d84fdd87fdd96515 100644
--- a/components/data_reduction_proxy/browser/data_reduction_proxy_protocol_unittest.cc
+++ b/components/data_reduction_proxy/browser/data_reduction_proxy_protocol_unittest.cc
@@ -13,6 +13,7 @@
 #include "base/strings/stringprintf.h"
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_params_test_utils.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/base/completion_callback.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/load_flags.h"
@@ -39,18 +40,6 @@ using net::URLRequest;
 using net::TestURLRequestContext;
 
 
-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 {
 
 // A test network delegate that exercises the bypass logic of the data