linux: enable seccomp sandbox by default

chrome/common/chrome_switches.h

Index: chrome/common/chrome_switches.h
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index a6ff6dacbdf7d0e91df13b5d68d7f98c276968ae..c2b50bfee1be9bd66ec02c4dec11f81fe583f01e 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -97,7 +97,6 @@ extern const char kEnableNaCl[];
 extern const char kEnableNativeWebWorkers[];
 extern const char kEnablePrivacyBlacklists[];
 extern const char kEnableRendererAccessibility[];
-extern const char kEnableSeccompSandbox[];
 extern const char kEnableStatsTable[];
 extern const char kEnableSync[];
 extern const char kEnableSyncAutofill[];
@@ -268,6 +267,14 @@ extern const char kInvalidateSyncXmppLogin[];
 extern const char kRendererCheckFalseTest[];
 #endif
 
+#if defined(USE_SECCOMP_SANDBOX)
+extern const char kDisableSeccompSandbox[];
+#else
+extern const char kEnableSeccompSandbox[];
+#endif
+// Return true if the switches indicate the seccomp sandbox is enabled.
+bool SeccompSandboxEnabled();
+
 // DON'T ADD RANDOM STUFF HERE. Put it in the main section above in
 // alphabetical order, or in one of the ifdefs (also in order in each section).