Linux: make current InitializeSandbox() private.

content/gpu/gpu_main.cc

Index: content/gpu/gpu_main.cc
diff --git a/content/gpu/gpu_main.cc b/content/gpu/gpu_main.cc
index 63f5273a34d444ff198e6d89e0dae77c9ae47baf..9eecda3cbe0c4172ba569b5583dd1d10cf549cfe 100644
--- a/content/gpu/gpu_main.cc
+++ b/content/gpu/gpu_main.cc
@@ -16,6 +16,7 @@
 #include "base/threading/platform_thread.h"
 #include "build/build_config.h"
 #include "content/common/gpu/gpu_config.h"
+#include "content/common/sandbox_linux.h"
 #include "content/gpu/gpu_child_thread.h"
 #include "content/gpu/gpu_info_collector.h"
 #include "content/gpu/gpu_process.h"
@@ -233,7 +234,7 @@ int GpuMain(const MainFunctionParams& parameters) {
     if (do_init_sandbox) {
       if (watchdog_thread.get())
         watchdog_thread->Stop();
-      gpu_info.sandboxed = InitializeSandbox();
+      gpu_info.sandboxed = LinuxSandbox::InitializeSandbox();
       if (watchdog_thread.get())
         watchdog_thread->Start();
     }