Improve process launch handle sharing API.

sandbox/linux/suid/client/setuid_sandbox_host.cc

Index: sandbox/linux/suid/client/setuid_sandbox_host.cc
diff --git a/sandbox/linux/suid/client/setuid_sandbox_host.cc b/sandbox/linux/suid/client/setuid_sandbox_host.cc
index 58cb8c712a71a4ac6e86f2e72dbbf09ad9bcd8fe..89836aaabb3dfc072cacb4c7edd62eced59e730c 100644
--- a/sandbox/linux/suid/client/setuid_sandbox_host.cc
+++ b/sandbox/linux/suid/client/setuid_sandbox_host.cc
@@ -165,10 +165,8 @@ void SetuidSandboxHost::PrependWrapper(base::CommandLine* cmd_line) {
 
 void SetuidSandboxHost::SetupLaunchOptions(
     base::LaunchOptions* options,
-    base::FileHandleMappingVector* fds_to_remap,
     base::ScopedFD* dummy_fd) {
   DCHECK(options);
-  DCHECK(fds_to_remap);
 
   // Launching a setuid binary requires PR_SET_NO_NEW_PRIVS to not be used.
   options->allow_new_privs = true;
@@ -183,7 +181,7 @@ void SetuidSandboxHost::SetupLaunchOptions(
   // We no longer need a dummy socket for discovering the child's PID,
   // but the sandbox is still hard-coded to expect a file descriptor at
   // kZygoteIdFd. Fixing this requires a sandbox API change. :(
-  fds_to_remap->push_back(std::make_pair(dummy_fd->get(), kZygoteIdFd));
+  options->fds_to_remap.push_back(std::make_pair(dummy_fd->get(), kZygoteIdFd));
 }
 
 void SetuidSandboxHost::SetupLaunchEnvironment() {