Reland of Add --headless flag to Windows

headless/app/headless_example.cc

 // Copyright 2017 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.
 
 // A small example application showing the use of the C++ Headless Chrome
 // library. It navigates to a web site given on the command line, waits for it
 // to load and prints out the DOM.
 //
 // Tip: start reading from the main() function below.
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/weak_ptr.h"
+#include "build/build_config.h"
 #include "headless/public/devtools/domains/page.h"
 #include "headless/public/devtools/domains/runtime.h"
 #include "headless/public/headless_browser.h"
 #include "headless/public/headless_devtools_client.h"
 #include "headless/public/headless_devtools_target.h"
 #include "headless/public/headless_web_contents.h"
 #include "ui/gfx/geometry/size.h"
 
+#if defined(OS_WIN)
+#include "content/public/app/sandbox_helper_win.h"
+#include "sandbox/win/src/sandbox_types.h"
+#endif
+
 // This class contains the main application logic, i.e., waiting for a page to
 // load and printing its DOM. Note that browser initialization happens outside
 // this class.
 class HeadlessExample : public headless::HeadlessWebContents::Observer,
                         public headless::page::Observer {
  public:
   HeadlessExample(headless::HeadlessBrowser* browser,
                   headless::HeadlessWebContents* web_contents);
   ~HeadlessExample() override;
 
@@ skipping 119 matching lines @@
   // setting the initial URL to navigate to.
   tab_builder.SetInitialURL(url);
 
   // Create an instance of the example app, which will wait for the page to load
   // and print its DOM.
   headless::HeadlessWebContents* web_contents = tab_builder.Build();
   g_example = new HeadlessExample(browser, web_contents);
 }
 
 int main(int argc, const char** argv) {
+#if !defined(OS_WIN)
   // This function must be the first thing we call to make sure child processes
   // such as the renderer are started properly. The headless library starts
   // child processes by forking and exec'ing the main application.
   headless::RunChildProcessIfNeeded(argc, argv);
+#endif
 
   // Create a headless browser instance. There can be one of these per process
   // and it can only be initialized once.
   headless::HeadlessBrowser::Options::Builder builder(argc, argv);
 
+#if defined(OS_WIN)
+  // In windows, you must initialize and set the sandbox, or pass it along
+  // if it has already been initialized.
+  sandbox::SandboxInterfaceInfo sandbox_info = {0};
+  content::InitializeSandboxInfo(&sandbox_info);
+  builder.SetSandboxInfo(&sandbox_info);
+#endif
   // Here you can customize browser options. As an example we set the window
   // size.
   builder.SetWindowSize(gfx::Size(800, 600));
 
   // Pass control to the headless library. It will bring up the browser and
   // invoke the given callback on the browser UI thread. Note: if you need to
   // pass more parameters to the callback, you can add them to the Bind() call
   // below.
   return headless::HeadlessBrowserMain(builder.Build(),
                                        base::Bind(&OnHeadlessBrowserStarted));
 }