Revert "Revert "Make shell child processes slaves.""

shell/child_process_host.cc

 // 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.
 
 #include "shell/child_process_host.h"
 
 #include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 17 matching lines @@
     : context_(context), channel_info_(nullptr) {
 }
 
 ChildProcessHost::~ChildProcessHost() {
   DCHECK(!child_process_.IsValid());
 }
 
 void ChildProcessHost::Start() {
   DCHECK(!child_process_.IsValid());
 
+  // TODO(vtl): Add something for |slave_info|.
+  mojo::embedder::ScopedPlatformHandle platform_handle_for_channel;
+  std::string child_connection_id;
+  mojo::embedder::ConnectToSlave(
+      nullptr, platform_channel_pair_.PassServerHandle(),
+      &platform_handle_for_channel, &child_connection_id);
+
   mojo::ScopedMessagePipeHandle handle(mojo::embedder::CreateChannel(
-      platform_channel_pair_.PassServerHandle(),
-      context_->task_runners()->io_runner(),
+      platform_handle_for_channel.Pass(), context_->task_runners()->io_runner(),
       base::Bind(&ChildProcessHost::DidCreateChannel, base::Unretained(this)),
       base::MessageLoop::current()->message_loop_proxy()));
 
   controller_.Bind(mojo::InterfacePtrInfo<ChildController>(handle.Pass(), 0u));
   controller_.set_error_handler(this);
 
   CHECK(base::PostTaskAndReplyWithResult(
       context_->task_runners()->blocking_pool(), FROM_HERE,
-      base::Bind(&ChildProcessHost::DoLaunch, base::Unretained(this)),
+      base::Bind(&ChildProcessHost::DoLaunch, base::Unretained(this),
+                 child_connection_id),
       base::Bind(&ChildProcessHost::DidStart, base::Unretained(this))));
 }
 
 int ChildProcessHost::Join() {
   DCHECK(child_process_.IsValid());
   int rv = -1;
   LOG_IF(ERROR, !child_process_.WaitForExit(&rv))
       << "Failed to wait for child process";
   child_process_.Close();
   return rv;
@@ skipping 29 matching lines @@
 
 // Callback for |mojo::embedder::CreateChannel()|.
 void ChildProcessHost::DidCreateChannel(
     mojo::embedder::ChannelInfo* channel_info) {
   DVLOG(2) << "ChildProcessHost::DidCreateChannel()";
 
   CHECK(channel_info);
   channel_info_ = channel_info;
 }
 
-bool ChildProcessHost::DoLaunch() {
+bool ChildProcessHost::DoLaunch(const std::string& child_connection_id) {
   static const char* kForwardSwitches[] = {
       switches::kTraceToConsole, switches::kV, switches::kVModule,
   };
 
   base::CommandLine child_command_line(context_->mojo_shell_child_path());
   child_command_line.CopySwitchesFrom(*base::CommandLine::ForCurrentProcess(),
                                       kForwardSwitches,
                                       arraysize(kForwardSwitches));
-  child_command_line.AppendSwitch(switches::kChildProcess);
+  child_command_line.AppendSwitchASCII(switches::kChildConnectionId,
+                                       child_connection_id);
 
   mojo::embedder::HandlePassingInformation handle_passing_info;
   platform_channel_pair_.PrepareToPassClientHandleToChildProcess(
       &child_command_line, &handle_passing_info);
 
   base::LaunchOptions options;
   options.fds_to_remap = &handle_passing_info;
   DVLOG(2) << "Launching child with command line: "
            << child_command_line.GetCommandLineString();
   child_process_ = base::LaunchProcess(child_command_line, options);
@@ skipping 10 matching lines @@
     on_app_complete_.reset();
     on_app_complete.Run(result);
   }
 }
 
 void ChildProcessHost::OnConnectionError() {
   AppCompleted(MOJO_RESULT_UNKNOWN);
 }
 
 }  // namespace shell