Re-apply r23841 "During uninstall if Chrome is set as default"

chrome/installer/util/shell_util.cc

 // Copyright (c) 2009 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.
 //
 // This file defines functions that integrate Chrome in Windows shell. These
 // functions can be used by Chrome as well as Chrome installer. All of the
 // work is done by the local functions defined in anonymous namespace in
 // this class.
 
 #include "chrome/installer/util/shell_util.h"
@@ skipping 565 matching lines @@
   } else {
     if (FAILED(SHGetFolderPath(NULL, CSIDL_APPDATA, NULL,
                                SHGFP_TYPE_CURRENT, qlaunch)))
       return false;
     *path = qlaunch;
   }
   file_util::AppendToPath(path, kQuickLaunchPath);
   return true;
 }
 
+void ShellUtil::GetRegisteredBrowsers(std::map<std::wstring,
+                                      std::wstring>* browsers) {
+  std::wstring base_key(ShellUtil::kRegStartMenuInternet);
+  HKEY root = HKEY_LOCAL_MACHINE;
+  for (RegistryKeyIterator iter(root, base_key.c_str()); iter.Valid(); ++iter) {
+    std::wstring key = base_key + L"\\" + iter.Name();
+    RegKey capabilities(root, (key + L"\\Capabilities").c_str());
+    std::wstring name;
+    if (!capabilities.Valid() ||
+        !capabilities.ReadValue(L"ApplicationName", &name)) {
+      RegKey base_key(root, key.c_str());
+      if (!base_key.ReadValue(L"", &name))
+        continue;
+    }
+    RegKey install_info(root, (key + L"\\InstallInfo").c_str());
+    std::wstring command;
+    if (!install_info.Valid() ||
+        !install_info.ReadValue(L"ReinstallCommand", &command))
+      continue;
+    BrowserDistribution* dist = BrowserDistribution::GetDistribution();
+    if (!name.empty() && !command.empty() &&
+        name.find(dist->GetApplicationName()) == std::wstring::npos)
+      (*browsers)[name] = command;
+  }
+}
+
 bool ShellUtil::GetUserSpecificDefaultBrowserSuffix(std::wstring* entry) {
   wchar_t user_name[256];
   DWORD size = _countof(user_name);
   if (::GetUserName(user_name, &size) == 0)
     return false;
   entry->assign(L".");
   entry->append(user_name);
 
   std::wstring start_menu_entry(ShellUtil::kRegStartMenuInternet);
   BrowserDistribution* dist = BrowserDistribution::GetDistribution();
@@ skipping 184 matching lines @@
   } else {
     return file_util::UpdateShortcutLink(chrome_exe.c_str(),      // target
                                          shortcut.c_str(),        // shortcut
                                          chrome_path.c_str(),     // working dir
                                          NULL,                    // arguments
                                          description.c_str(),     // description
                                          chrome_exe.c_str(),      // icon file
                                          0);                      // icon index
   }
 }