Linux: initialize the sandbox in the Plugin process.

content/plugin/plugin_main.cc

Index: content/plugin/plugin_main.cc
diff --git a/content/plugin/plugin_main.cc b/content/plugin/plugin_main.cc
index 14db48e08ce6191552f55baccd687894b164194c..1cb408f040a404f431ce46e0726aecdbb1dd4268 100644
--- a/content/plugin/plugin_main.cc
+++ b/content/plugin/plugin_main.cc
@@ -20,6 +20,7 @@
 #include "content/plugin/plugin_thread.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
+#include "content/public/common/sandbox_init.h"
 
 #if defined(OS_WIN)
 #include "content/public/common/injection_test_win.h"
@@ -175,6 +176,10 @@ int PluginMain(const content::MainFunctionParams& parameters) {
   }
 
   {
+#if defined(OS_LINUX)
+    // Go through Linux sandbox initialization before starting any thread.
+    content::InitializeSandbox();
+#endif
     ChildProcess plugin_process;
     plugin_process.set_main_thread(new PluginThread());
 #if defined(OS_WIN)