Fix "unused variable" warnings.

content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc

Index: content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc
diff --git a/content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc b/content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc
index 7a3620ccf667abf92be59f6caf8b3bcf4369f1f7..4fd335b2e0d00efb38dc5e0e0c2dcdb9d1b44c74 100644
--- a/content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc
+++ b/content/common/sandbox_linux/sandbox_seccomp_bpf_linux.cc
@@ -164,13 +164,9 @@ void RunSandboxSanityChecks(const std::string& process_type) {
 std::unique_ptr<SandboxBPFBasePolicy> GetGpuProcessSandbox() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
-  bool allow_sysv_shm = false;
-  if (command_line.HasSwitch(switches::kGpuSandboxAllowSysVShm)) {
-    DCHECK(IsArchitectureArm());

[Peter Kasting, 2016/05/19 05:32:37]

Technically this DCHECK is incorrect; it's perfectly possible for someone to
pass this command-line flag while on the wrong architecture.  It won't do
anything in that case anyway, so there's no real reason to bother DCHECKing.

-    allow_sysv_shm = true;
-  }
-
   if (IsChromeOS() && IsArchitectureArm()) {
+    bool allow_sysv_shm =
+        command_line.HasSwitch(switches::kGpuSandboxAllowSysVShm);
     return std::unique_ptr<SandboxBPFBasePolicy>(
         new CrosArmGpuProcessPolicy(allow_sysv_shm));
   } else {