Make SandboxIPCProcess a thread.

content/browser/renderer_host/render_sandbox_host_linux.h

Index: content/browser/renderer_host/render_sandbox_host_linux.h
diff --git a/content/browser/renderer_host/render_sandbox_host_linux.h b/content/browser/renderer_host/render_sandbox_host_linux.h
index 2c5df388bd29f84540d179947420c4ca22158efc..6c88dcc6a90cc632a165dd82cff4d040f7a8a331 100644
--- a/content/browser/renderer_host/render_sandbox_host_linux.h
+++ b/content/browser/renderer_host/render_sandbox_host_linux.h
@@ -8,6 +8,9 @@
 #include <string>
 
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/simple_thread.h"
+#include "content/browser/renderer_host/sandbox_ipc_linux.h"
 #include "content/common/content_export.h"
 
 template <typename T> struct DefaultSingletonTraits;
@@ -27,10 +30,6 @@ class CONTENT_EXPORT RenderSandboxHostLinux {
     DCHECK(initialized_);
     return renderer_socket_;
   }
-  pid_t pid() const {
-    DCHECK(initialized_);
-    return pid_;
-  }
   void Init(const std::string& sandbox_path);
 
  private:
@@ -43,8 +42,9 @@ class CONTENT_EXPORT RenderSandboxHostLinux {
   bool initialized_;
 
   int renderer_socket_;
-  int childs_lifeline_fd_;
-  pid_t pid_;
+
+  scoped_ptr<SandboxIPCHandler> ipc_handler_;
+  scoped_ptr<base::DelegateSimpleThread> ipc_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderSandboxHostLinux);
 };