Fix nacl_integration to run 32bit tests with 32bit userland and 64bit kernel.

chrome/test/nacl_test_injection/buildbot_chrome_nacl_stage.py

Index: chrome/test/nacl_test_injection/buildbot_chrome_nacl_stage.py
diff --git a/chrome/test/nacl_test_injection/buildbot_chrome_nacl_stage.py b/chrome/test/nacl_test_injection/buildbot_chrome_nacl_stage.py
index ca198f4a19fdd5d9b916157d733f466aa8e6dd91..ab888f38f4f240823303ca2b26a5dfa35231111f 100755
--- a/chrome/test/nacl_test_injection/buildbot_chrome_nacl_stage.py
+++ b/chrome/test/nacl_test_injection/buildbot_chrome_nacl_stage.py
@@ -15,6 +15,11 @@ import sys
 
 import find_chrome
 
+THIS_DIR = os.path.abspath(os.path.dirname(__file__))
+CHROMIUM_DIR = os.path.abspath(os.path.join(THIS_DIR, '..', '..', '..'))
+sys.path.append(os.path.join(CHROMIUM_DIR, 'build'))
+import detect_host_arch
+
 
 # Copied from buildbot/buildbot_lib.py
 def TryToCleanContents(path, file_name_filter=lambda fn: True):
@@ -149,17 +154,11 @@ def BuildAndTest(options):
         bits = 32
     scons = [python, 'scons.py']
   else:
-    p = subprocess.Popen(
-        'uname -m | '
-        'sed -e "s/i.86/ia32/;s/x86_64/x64/;s/amd64/x64/;s/arm.*/arm/"',
-        shell=True, stdout=subprocess.PIPE)
-    (p_stdout, _) = p.communicate()
-    assert p.returncode == 0
     if options.bits == 64:
       bits = 64
     elif options.bits == 32:
       bits = 32
-    elif p_stdout.find('64') >= 0:
+    elif '64' in detect_host_arch.HostArch():
       bits = 64
     else:
       bits = 32