Add --enable-seccomp-filter-sandbox to about:flags on Android.

content/renderer/renderer_main_platform_delegate_android.cc

Index: content/renderer/renderer_main_platform_delegate_android.cc
diff --git a/content/renderer/renderer_main_platform_delegate_android.cc b/content/renderer/renderer_main_platform_delegate_android.cc
index b4eef97b6babcd092d43ad4c86126c38b7814a19..8ef130375a7f62d9e6a790ef23f415e84985d6df 100644
--- a/content/renderer/renderer_main_platform_delegate_android.cc
+++ b/content/renderer/renderer_main_platform_delegate_android.cc
@@ -35,6 +35,12 @@ bool RendererMainPlatformDelegate::EnableSandbox() {
           switches::kEnableSeccompFilterSandbox)) {
     return true;
   }
+  if (!sandbox::SandboxBPF::SupportsSeccompSandbox(
+          sandbox::SandboxBPF::SeccompLevel::MULTI_THREADED)) {
+    LOG(WARNING) << "Seccomp-BPF sandbox enabled without kernel support. "
+                 << "Ignoring flag and proceeding without seccomp sandbox.";
+    return true;
+  }
 
   sandbox::SandboxBPF sandbox(new SandboxBPFBasePolicyAndroid());
   CHECK(