sandbox: add missing header files to the corresponding BUILD.gn file

sandbox/linux/BUILD.gn

Index: sandbox/linux/BUILD.gn
diff --git a/sandbox/linux/BUILD.gn b/sandbox/linux/BUILD.gn
index 3e98defa5c612f298631edb395a8146c82436edf..d250d216acc11f0d4c49c89779055cd33990c2c7 100644
--- a/sandbox/linux/BUILD.gn
+++ b/sandbox/linux/BUILD.gn
@@ -391,14 +391,19 @@ source_set("sandbox_services_headers") {
     "system_headers/arm_linux_syscalls.h",
     "system_headers/arm_linux_ucontext.h",
     "system_headers/i386_linux_ucontext.h",
+    "system_headers/linux_filter.h",
     "system_headers/linux_futex.h",
     "system_headers/linux_seccomp.h",
     "system_headers/linux_signal.h",
     "system_headers/linux_syscalls.h",
     "system_headers/linux_time.h",
     "system_headers/linux_ucontext.h",
+    "system_headers/mips64_linux_syscalls.h",
+    "system_headers/mips_linux_syscalls.h",
+    "system_headers/mips_linux_ucontext.h",
     "system_headers/x86_32_linux_syscalls.h",
     "system_headers/x86_64_linux_syscalls.h",
+    "system_headers/x86_64_linux_ucontext.h",
   ]
 }