Correcting the version field in the Chrome-Proxy header to be the chromium build and patch number.

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 abdbe4bd60e623134369db81ff2249744cc6cdaf..4b57a17ea63a3f80805cd05671b6a3120d041c96 100644
--- a/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
+++ b/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 
+#include "base/strings/string_split.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_configurator.h"
 #include "chrome/browser/profiles/profile.h"
@@ -38,3 +39,11 @@ void DataReductionProxyChromeSettings::InitDataReductionProxySettings(
   SetDataReductionProxyAlternativeEnabled(
       DataReductionProxyParams::IsIncludedInAlternativeFieldTrial());
 }
+
+// static
+std::string DataReductionProxyChromeSettings::GetBuildAndPatchNumber(
+    const std::string& version) {
+  std::vector<std::string> version_parts;
+  base::SplitString(version, '.', &version_parts);

[bengr, 2014/07/31 18:22:40]

You should check that the vector size is 4.
Optional: for symmetry, you could erase the first two elements and then call
JoinString

[megjablon, 2014/07/31 20:48:36]

Done.

+  return version_parts[2] + "." + version_parts[3];
+}