Add build and patch to Chrome-Proxy header

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc

Index: chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
diff --git a/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc b/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
index 26be2de2cd7dc939dba07a2f3d4b57d189009c0c..6776cd7ab88c388d5b2807b230236b45c883c261 100644
--- a/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
+++ b/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
@@ -56,11 +56,17 @@ void DataReductionProxyChromeSettings::RegisterSyntheticFieldTrial(
 // static
 std::string DataReductionProxyChromeSettings::GetBuildAndPatchNumber() {
   chrome::VersionInfo version_info;
+  return GetBuildAndPatchNumberFromString(version_info.Version());
+}
+
+// static
+std::string DataReductionProxyChromeSettings::GetBuildAndPatchNumberFromString(
+    std::string version) {
   std::vector<std::string> version_parts;
-  base::SplitString(version_info.Version(), '.', &version_parts);
+  base::SplitString(version, '.', &version_parts);
   if (version_parts.size() != 4)
-    return "";
-  return version_parts[2] + version_parts[3];
+    return std::string();
+  return version_parts[2] + '.' + version_parts[3];
 }
 
 // static