Uninstall Chrome + has App Host + not App Launcher => Uninstall App Host.

chrome/installer/util/installer_state.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 "chrome/installer/util/installer_state.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 
@@ skipping 114 matching lines @@
     VLOG(1) << (is_uninstall ? "Uninstall" : "Install")
             << " distribution: " << p->distribution()->GetAppShortCutName();
   }
   if (prefs.install_chrome_frame()) {
     Product* p =
         AddProductFromPreferences(BrowserDistribution::CHROME_FRAME, prefs,
                                   machine_state);
     VLOG(1) << (is_uninstall ? "Uninstall" : "Install")
             << " distribution: " << p->distribution()->GetAppShortCutName();
   }
-  if (prefs.install_chrome_app_host()) {
+
+  // If Chrome is being uninstalled, and (non-App Launcher) App Host exists,

[grt (UTC plus 2), 2012/11/16 04:25:17]

suggest "Uninstall App Host if Chrome is being uninstalled and (non-App
Launcher) App Host exists."

[grt (UTC plus 2), 2012/11/16 04:25:17]

please consider if this logic belongs in the "if (is_uninstall &&
prefs.is_multi_install())" block below (i think it does).

[huangs, 2012/11/16 16:48:57]

Done.  Added more comments regarding mix of system/user levels.

[huangs, 2012/11/16 16:48:57]

Done, but with slight code duplication.

+  // then also uninstall App Host.
+  bool also_uninstall_app_host = false;
+  if (is_uninstall && prefs.install_chrome()) {
+    bool system_level_app_host = false;

[erikwright (departed), 2012/11/16 02:59:19]

I don't see the merit of this boolean variable, nor fixing it to false. I think
it's OK to go ahead and look at the same level from which we are uninstalling
Chrome.

Do not uninstall the app host if this is a user-level uninstall and a
system-level Chrome is present.

[huangs, 2012/11/16 16:48:57]

Done.

+    const ProductState* app_host_state = machine_state.GetProductState(
+        system_level_app_host, BrowserDistribution::CHROME_APP_HOST);
+    also_uninstall_app_host = app_host_state &&
+        !CommandLine(app_host_state->uninstall_command())

[grt (UTC plus 2), 2012/11/16 04:25:17]

!app_host_state->uninstall_command().HasSwitch(...)

[huangs, 2012/11/16 16:48:57]

Done.  Also fixing same goof in install.cc

+            .HasSwitch(switches::kChromeAppLauncher);
+  }
+
+  if (prefs.install_chrome_app_host() || also_uninstall_app_host) {
+    if (!prefs.install_chrome_app_host()) {
+      VLOG(1) << "Uninstalling App Host along with Chrome.";
+    }
     Product* p =
         AddProductFromPreferences(BrowserDistribution::CHROME_APP_HOST, prefs,
                                   machine_state);
     VLOG(1) << (is_uninstall ? "Uninstall" : "Install")
             << " distribution: " << p->distribution()->GetAppShortCutName();
   }
 
   if (!is_uninstall && is_multi_install()) {
     bool need_binaries = false;
     if (FindProduct(BrowserDistribution::CHROME_APP_HOST)) {
@@ skipping 617 matching lines @@
   if (is_multi_install()) {
     InstallUtil::AddInstallerResultItems(
         system_install, multi_package_binaries_distribution()->GetStateKey(),
         status, string_resource_id, launch_cmd, install_list.get());
   }
   if (!install_list->Do())
     LOG(ERROR) << "Failed to record installer error information in registry.";
 }
 
 }  // namespace installer