mandoline sandbox: prewarm libraries before we raise the sandbox.

mojo/runner/desktop/main.cc

Index: mojo/runner/desktop/main.cc
diff --git a/mojo/runner/desktop/main.cc b/mojo/runner/desktop/main.cc
index 1764c3f110008845807b793be043b98fdb7c5e87..47e636c7bf722230bb60221e2e18da24750bffc6 100644
--- a/mojo/runner/desktop/main.cc
+++ b/mojo/runner/desktop/main.cc
@@ -4,9 +4,11 @@
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
+#include "base/files/file_path.h"
 #include "mojo/runner/child_process.h"
 #include "mojo/runner/desktop/launcher_process.h"
 #include "mojo/runner/init.h"
+#include "mojo/runner/native_application_support.h"
 #include "mojo/runner/switches.h"
 
 int main(int argc, char** argv) {
@@ -17,8 +19,16 @@ int main(int argc, char** argv) {
 
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
-  if (command_line.HasSwitch(switches::kChildProcess))
-    return mojo::runner::ChildProcessMain();
+  if (command_line.HasSwitch(switches::kChildProcess)) {
+    mojo::shell::NativeApplicationCleanup cleanup =
+        command_line.HasSwitch(switches::kDeleteAfterLoad)
+            ? mojo::shell::NativeApplicationCleanup::DELETE
+            : mojo::shell::NativeApplicationCleanup::DONT_DELETE;
+    base::NativeLibrary app_library = mojo::runner::LoadNativeApplication(
+        command_line.GetSwitchValuePath(switches::kChildProcess), cleanup);
+
+    return mojo::runner::ChildProcessMain(app_library);
+  }
 
   return mojo::runner::LauncherProcessMain(argc, argv);
 }