mandoline sandbox: prewarm libraries before we raise the sandbox.

mojo/runner/child_process.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module mojo.runner;
 
 import "mojo/application/public/interfaces/application.mojom";
 
 interface ChildController {
-  // Starts the app at the given path (deleting it if |clean_app_path| is true).
-  StartApp(string app_path,
-           bool clean_app_path,
-           mojo.Application& application_request) => (int32 result);
+  // Starts the app.
+  StartApp(mojo.Application& application_request) => (int32 result);
 
   // Exits the child process now (with no cleanup), with the given exit code.
   ExitNow(int32 exit_code);
 };