Fix user-level Chrome self-destruction issues on Windows 8.

chrome/browser/chrome_browser_main_win.cc

Index: chrome/browser/chrome_browser_main_win.cc
diff --git a/chrome/browser/chrome_browser_main_win.cc b/chrome/browser/chrome_browser_main_win.cc
index 10ed28d3807543761ded08f6d77fd3101b70667a..3da771b9c16db20086d3ca44d8840450f58e3e9e 100644
--- a/chrome/browser/chrome_browser_main_win.cc
+++ b/chrome/browser/chrome_browser_main_win.cc
@@ -361,18 +361,27 @@ bool ChromeBrowserMainPartsWin::CheckMachineLevelInstall() {
     std::wstring exe = exe_path.value();
     FilePath user_exe_path(installer::GetChromeInstallPath(false, dist));
     if (FilePath::CompareEqualIgnoreCase(exe, user_exe_path.value())) {
-      const string16 text =
-          l10n_util::GetStringUTF16(IDS_MACHINE_LEVEL_INSTALL_CONFLICT);
-      const string16 caption = l10n_util::GetStringUTF16(IDS_PRODUCT_NAME);
-      const UINT flags = MB_OK | MB_ICONERROR | MB_TOPMOST;
-      ui::MessageBox(NULL, text, caption, flags);
+      if (base::win::GetVersion() < base::win::VERSION_WIN8 ||
+          !base::win::IsMetroProcess()) {
+        // The dialog cannot be shown in Win8 Metro as doing so hangs Chrome on
+        // an invisible dialog.
+        // TODO (gab): Get rid of this dialog altogether and auto-launch
+        // system-level Chrome instead.
+        const string16 text =
+            l10n_util::GetStringUTF16(IDS_MACHINE_LEVEL_INSTALL_CONFLICT);
+        const string16 caption = l10n_util::GetStringUTF16(IDS_PRODUCT_NAME);
+        const UINT flags = MB_OK | MB_ICONERROR | MB_TOPMOST;
+        ui::MessageBox(NULL, text, caption, flags);
+      }
       CommandLine uninstall_cmd(
           InstallUtil::GetChromeUninstallCmd(false, dist->GetType()));
       if (!uninstall_cmd.GetProgram().empty()) {
         uninstall_cmd.AppendSwitch(installer::switches::kForceUninstall);
         uninstall_cmd.AppendSwitch(
             installer::switches::kDoNotRemoveSharedItems);
-        base::LaunchProcess(uninstall_cmd, base::LaunchOptions(), NULL);
+        base::LaunchOptions launch_options;
+        launch_options.force_breakaway_from_job_ = true;

[grt (UTC plus 2), 2012/11/20 02:35:38]

i'm a bit concerned about always doing this.  as it happens, BREAKAWAY_FROM_JOB
messes with the environment set up by Citrix (see
https://code.google.com/p/chromium/issues/detail?id=79091#c45). can you make it
so that the breakaway is only done for Win8+IsMetroProcess?

[gab, 2012/11/20 15:38:06]

Done.

+        base::LaunchProcess(uninstall_cmd, launch_options, NULL);
       }
       return true;
     }