Parse /etc/lsb-release only once on ChromeOS

chrome/browser/chromeos/external_metrics.cc

Index: chrome/browser/chromeos/external_metrics.cc
diff --git a/chrome/browser/chromeos/external_metrics.cc b/chrome/browser/chromeos/external_metrics.cc
index b0ae2988743963e81b9293c8930d80a5cab56e36..f8da0d349f658e90c170f64acb6469b810748613 100644
--- a/chrome/browser/chromeos/external_metrics.cc
+++ b/chrome/browser/chromeos/external_metrics.cc
@@ -103,11 +103,7 @@ void SetupProgressiveScanFieldTrial() {
 // mess.  At least this code is temporary.
 
 bool Is2GBParrot() {
-  base::FilePath path("/etc/lsb-release");
-  std::string contents;
-  if (!base::ReadFileToString(path, &contents))
-    return false;
-  if (contents.find("CHROMEOS_RELEASE_BOARD=parrot") == std::string::npos)
+  if (base::SysInfo::GetLsbReleaseBoard() != "parrot")
     return false;
   // There are 2GB and 4GB models.
   return base::SysInfo::AmountOfPhysicalMemory() <= 2LL * 1024 * 1024 * 1024;