[Chromoting] Refactored worker process launching code and speeded up the desktop process launch.

remoting/host/win/wts_console_session_process_driver.cc

 // Copyright (c) 2012 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 "remoting/host/win/wts_console_session_process_driver.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
+#include "base/win/windows_version.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_macros.h"
 #include "remoting/host/chromoting_messages.h"
 #include "remoting/host/host_main.h"
 #include "remoting/host/ipc_constants.h"
 #include "remoting/host/sas_injector.h"
 #include "remoting/host/win/worker_process_launcher.h"
 #include "remoting/host/win/wts_session_process_delegate.h"
 #include "remoting/host/win/wts_terminal_monitor.h"
 
@@ skipping 60 matching lines @@
 
 void WtsConsoleSessionProcessDriver::OnSessionAttached(uint32 session_id) {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
   if (stoppable_state() != Stoppable::kRunning) {
     return;
   }
 
   DCHECK(launcher_.get() == NULL);
 
-  // Get the host binary name.
+  // Launch elevated on Win8 to be able to inject Alt+Tab.
+  bool launch_elevated = base::win::GetVersion() >= base::win::VERSION_WIN8;
+
+  // Get the name of the executable the desktop process will run.
   base::FilePath desktop_binary;
-  if (!GetInstalledBinaryPath(kDesktopBinaryName, &desktop_binary)) {
+  bool result;
+  if (launch_elevated) {
+    result = GetInstalledBinaryPath(kDesktopBinaryName, &desktop_binary);
+  } else {
+    result = GetInstalledBinaryPath(kHostBinaryName, &desktop_binary);
+  }
+
+  if (!result) {
     Stop();
     return;
   }
 
   scoped_ptr<CommandLine> target(new CommandLine(desktop_binary));
   target->AppendSwitchASCII(kProcessTypeSwitchName, kProcessTypeHost);
   target->CopySwitchesFrom(*CommandLine::ForCurrentProcess(),
                            kCopiedSwitchNames,
                            arraysize(kCopiedSwitchNames));
 
   // Create a Delegate capable of launching an elevated process in the session.
   scoped_ptr<WtsSessionProcessDelegate> delegate(
-      new WtsSessionProcessDelegate(caller_task_runner_,
-                                    io_task_runner_,
+      new WtsSessionProcessDelegate(io_task_runner_,
                                     target.Pass(),
-                                    session_id,
-                                    true,
+                                    launch_elevated,
                                     kDaemonIpcSecurityDescriptor));
+  if (!delegate->Initialize(session_id)) {
+    Stop();
+    return;
+  }
 
   // Use the Delegate to launch the host process.
-  launcher_.reset(new WorkerProcessLauncher(
-      caller_task_runner_, delegate.Pass(), this));
+  launcher_.reset(new WorkerProcessLauncher(delegate.Pass(), this));
 }
 
 void WtsConsoleSessionProcessDriver::OnSessionDetached() {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
   DCHECK(launcher_.get() != NULL);
 
   launcher_.reset();
 }
 
 void WtsConsoleSessionProcessDriver::DoStop() {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
   launcher_.reset();
   CompleteStopping();
 }
 
 void WtsConsoleSessionProcessDriver::OnSendSasToConsole() {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
   if (!launcher_)
     return;
 
   if (!sas_injector_)
     sas_injector_ = SasInjector::Create();
   if (!sas_injector_->InjectSas())
     LOG(ERROR) << "Failed to inject Secure Attention Sequence.";
 }
 
 } // namespace remoting