Add ARC version to help and version pages

chromeos/system/version_loader.cc

Index: chromeos/system/version_loader.cc
diff --git a/chromeos/system/version_loader.cc b/chromeos/system/version_loader.cc
index f62ea0668d4fdcf852fb279408d34e0c599874bf..e5d0a297b49bf673e95e65239ebef78fab924419 100644
--- a/chromeos/system/version_loader.cc
+++ b/chromeos/system/version_loader.cc
@@ -29,6 +29,9 @@ const char kFullVersionKey[] = "CHROMEOS_RELEASE_DESCRIPTION";
 // Same but for short version (x.x.xx.x).
 const char kVersionKey[] = "CHROMEOS_RELEASE_VERSION";
 
+// Same but for ARC version.
+const char kArcVersionKey[] = "CHROMEOS_ARC_VERSION";
+
 // Beginning of line we look for that gives the firmware version.
 const char kFirmwarePrefix[] = "version";
 
@@ -58,6 +61,15 @@ std::string GetVersion(VersionFormat format) {
   return version;
 }
 
+std::string GetARCVersion() {
+  std::string version;
+  if (!base::SysInfo::GetLsbReleaseValue(kArcVersionKey, &version)) {
+    LOG_IF(ERROR, base::SysInfo::IsRunningOnChromeOS())
+        << "No LSB version key: " << kArcVersionKey;
+  }
+  return version;
+}
+
 std::string GetFirmware() {
   std::string firmware;
   std::string contents;