Revert of Disable yama on 3.2 kernels with 32bit userland and 64bit kernel.

Revert of Disable yama on 3.2 kernels with 32bit userland and 64bit kernel. (https://codereview.chromium.org/371113003/)

Reason for revert:
This seems to be breaking Linux builds:

http://build.chromium.org/p/chromium/builders/Linux/builds/51190
http://build.chromium.org/p/chromium.linux/builders/Linux%20Builder%20%28dbg%29%2832%29/builds/26110

Original issue's description:
> Disable two yama tests on 3.2 kernels with 32bit userland and 64bit kernel.
> 
> Disabling yama restrictions is broken there.
> 
> BUG=391916
> R=jorgelo@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281666

TBR=jorgelo@chromium.org,keescook@chromium.org,thakis@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=391916

[nhiroki, 2014-07-08 05:54:49]

Created Revert of Disable yama on 3.2 kernels with 32bit userland and 64bit
kernel.

[commit-bot: I haz the power, 2014-07-08 05:55:39]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/nhiroki@chromium.org/378793002/1

[commit-bot: I haz the power, 2014-07-08 05:56:35]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-08 05:56:36]

Failed to apply patch for sandbox/linux/services/yama_unittests.cc:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file sandbox/linux/services/yama_unittests.cc
  Hunk #1 FAILED at 20.
  1 out of 3 hunks FAILED -- saving rejects to file
sandbox/linux/services/yama_unittests.cc.rej

Patch:       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
eb783d97c333aa92506b7627ec7b490dccddba64..17ef4b40de5a046286296eab9fafb8302e6ac2cb
100644
--- a/sandbox/linux/services/yama_unittests.cc
+++ b/sandbox/linux/services/yama_unittests.cc
@@ -20,21 +20,6 @@
 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;
-}
 
 bool CanPtrace(pid_t pid) {
   int ret;
@@ -127,9 +112,6 @@
 }
 
 TEST(Yama, RestrictPtraceWorks) {
-  if (HasLinux32Bug())
-    return;
-
   ScopedProcess process1(base::Bind(&SetYamaRestrictions, true));
   ASSERT_TRUE(process1.WaitForClosureToRun());
 
@@ -152,7 +134,7 @@
 void DoNothing() {}
 
 SANDBOX_TEST(Yama, RestrictPtraceIsDefault) {
-  if (!Yama::IsPresent() || HasLinux32Bug())
+  if (!Yama::IsPresent())
     return;
 
   CHECK(Yama::DisableYamaRestrictions());

[nhiroki, 2014-07-08 06:05:12]

Reverted this using drover: https://codereview.chromium.org/376793002/

[Nico, 2014-07-08 15:25:16]

lgtm, thanks

(could've just added the includes, though)