Add build and patch to Chrome-Proxy header

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.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 "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_split.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 36 matching lines @@
 }
 
 void DataReductionProxyChromeSettings::RegisterSyntheticFieldTrial(
     bool data_reduction_proxy_enabled) {
   ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
       "DataReductionProxyEnabled",
       data_reduction_proxy_enabled ? "true" : "false");
 }
 
 // static
-std::string DataReductionProxyChromeSettings::GetBuildAndPatchNumber() {
+std::string DataReductionProxyChromeSettings::GetBuildNumber() {
   chrome::VersionInfo version_info;
-  std::vector<std::string> version_parts;
-  base::SplitString(version_info.Version(), '.', &version_parts);
-  if (version_parts.size() != 4)
-    return "";
-  return version_parts[2] + version_parts[3];
+  return GetBuildNumberFromString(version_info.Version());
 }
 
 // static
+std::string DataReductionProxyChromeSettings::GetBuildNumberFromString(

[bengr, 2014/09/03 22:28:38]

How often is this called? If once, I'm ok with the structure. If it's on every
request, then to avoid copies, do bool GetBuildNumberFromString(std::string*
build_number);

[megjablon, 2014/09/04 00:41:06]

Only once

+    std::string version) {
+  std::vector<std::string> version_parts;
+  base::SplitString(version, '.', &version_parts);
+  if (version_parts.size() != 4)
+    return std::string();
+  return version_parts[2];
+}
+
+// static
+std::string DataReductionProxyChromeSettings::GetPatchNumber() {

[bengr, 2014/09/03 22:28:39]

To avoid repetition, I'd have one function called void
GetChromiumVersionComponent(const std::string& version, size_t component_index);

Then have GetBuildNumberFromString call
GetChromiumVersionComponent(version_info.Version(), 2) and have
GetPatchNumberFromString call
GetChromiumVersionComponent(version_info.Version(), 3)

+  chrome::VersionInfo version_info;
+  return GetPatchNumberFromString(version_info.Version());
+}
+
+// static
+std::string DataReductionProxyChromeSettings::GetPatchNumberFromString(
+    std::string version) {
+  std::vector<std::string> version_parts;
+  base::SplitString(version, '.', &version_parts);
+  if (version_parts.size() != 4)
+    return std::string();
+  return version_parts[3];
+}
+
+// static
 std::string DataReductionProxyChromeSettings::GetClient() {
 #if defined(OS_ANDROID)
   return data_reduction_proxy::kClientChromeAndroid;
 #elif defined(OS_IOS)
   return data_reduction_proxy::kClientChromeIOS;
 #else
   return "";
 #endif
 }