[MIPS] Add seccomp bpf support

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 93016e2db7d0aff8f5e361f3fcac5223486d14c2..246b1e0c1e00c297bcafd13a3596956d0e7d1cc1 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -2256,13 +2256,13 @@
         'chromium_win_pch': 0,
       }],
 
-      # The seccomp-bpf sandbox is only supported on three architectures
+      # The seccomp-bpf sandbox is only supported on four architectures
       # currently.
       # Do not disable seccomp_bpf anywhere without talking to
       # security@chromium.org!
       ['((OS=="linux" or OS=="android") and '
            '(target_arch=="ia32" or target_arch=="x64" or '
-             'target_arch=="arm"))', {
+             'target_arch=="arm" or target_arch=="mipsel"))', {
          'use_seccomp_bpf%': 1,
       }, {
          'use_seccomp_bpf%': 0,