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

remoting/host/desktop_session_win.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/desktop_session_win.h"
 
 #include <limits>
 #include <sddl.h>
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/path_service.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer.h"
 #include "base/utf_string_conversions.h"
 #include "base/win/scoped_comptr.h"
 #include "base/win/scoped_handle.h"
+#include "base/win/windows_version.h"
 #include "ipc/ipc_message_macros.h"
 #include "ipc/ipc_platform_file.h"
 #include "net/base/ip_endpoint.h"
 #include "remoting/base/auto_thread_task_runner.h"
 // MIDL-generated declarations and definitions.
 #include "remoting/host/chromoting_lib.h"
 #include "remoting/host/chromoting_messages.h"
 #include "remoting/host/daemon_process.h"
 #include "remoting/host/desktop_session.h"
 #include "remoting/host/host_main.h"
@@ skipping 472 matching lines @@
   daemon_process()->CloseDesktopSession(id());
 }
 
 void DesktopSessionWin::OnSessionAttached(uint32 session_id) {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
   DCHECK(!launcher_);
   DCHECK(monitoring_notifications_);
 
   ReportElapsedTime("attached");
 
-  // Get the name of the executable the desktop process will run.
+  // 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 to run. |kDesktopBinaryName| specifies
+  // uiAccess="true" in it's manifest.
   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) {
     OnPermanentError();
     return;
   }
 
   session_attach_timer_.Stop();
 
   scoped_ptr<CommandLine> target(new CommandLine(desktop_binary));
   target->AppendSwitchASCII(kProcessTypeSwitchName, kProcessTypeDesktop);
   // Copy the command line switches enabling verbose logging.
   target->CopySwitchesFrom(*CommandLine::ForCurrentProcess(),
                            kCopiedSwitchNames,
                            arraysize(kCopiedSwitchNames));
 
   // Create a delegate capable of launching a process in a different session.
   scoped_ptr<WtsSessionProcessDelegate> delegate(
-      new WtsSessionProcessDelegate(
-          caller_task_runner_, io_task_runner_, target.Pass(), session_id, true,
-          WideToUTF8(kDaemonIpcSecurityDescriptor)));
+      new WtsSessionProcessDelegate(io_task_runner_,
+                                    target.Pass(),
+                                    launch_elevated,
+                                    WideToUTF8(kDaemonIpcSecurityDescriptor)));
+  if (!delegate->Initialize(session_id)) {
+    OnPermanentError();
+    return;
+  }
 
   // Create a launcher for the desktop process, using the per-session delegate.
-  launcher_.reset(new WorkerProcessLauncher(
-      caller_task_runner_, delegate.Pass(), this));
+  launcher_.reset(new WorkerProcessLauncher(delegate.Pass(), this));
 }
 
 void DesktopSessionWin::OnSessionDetached() {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
   launcher_.reset();
 
   if (monitoring_notifications_) {
     ReportElapsedTime("detached");
 
@@ skipping 36 matching lines @@
                                 exploded.hour,
                                 exploded.minute,
                                 exploded.second,
                                 exploded.millisecond,
                                 passed.c_str());
 
   last_timestamp_ = now;
 }
 
 }  // namespace remoting