yama test workaround: Do feature detection, not OS version sniffing.

sandbox/linux/services/yama_unittests.cc

Index: sandbox/linux/services/yama_unittests.cc
diff --git a/sandbox/linux/services/yama_unittests.cc b/sandbox/linux/services/yama_unittests.cc
index a4100a6c37d346d0ca5af6e230444f3bc44cb596..7d4acc71e27efb9cd169605d4f9a956b176b35ce 100644
--- a/sandbox/linux/services/yama_unittests.cc
+++ b/sandbox/linux/services/yama_unittests.cc
@@ -24,18 +24,10 @@ namespace sandbox {
 namespace {
 
 bool HasLinux32Bug() {
-#if defined(__i386__)
   // On 3.2 kernels, yama doesn't work for 32-bit binaries on 64-bit kernels.
   // This is fixed in 3.4.
-  bool is_kernel_64bit =
-      base::SysInfo::OperatingSystemArchitecture() == "x86_64";
-  bool is_linux = base::SysInfo::OperatingSystemName() == "Linux";
-  bool is_3_dot_2 = StartsWithASCII(
-      base::SysInfo::OperatingSystemVersion(), "3.2", /*case_sensitive=*/false);
-  if (is_kernel_64bit && is_linux && is_3_dot_2)
-    return true;
-#endif  // defined(__i386__)
-  return false;
+  return prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0) < 0 &&
+         errno == EINVAL;
 }
 
 bool CanPtrace(pid_t pid) {