Fix in-use updates for Chrome Frame.

chrome/installer/util/copy_reg_key_work_item.cc

 // Copyright (c) 2011 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/copy_reg_key_work_item.h"
 
 #include <shlwapi.h>
 
 #include "base/logging.h"
 #include "base/win/registry.h"
 
 using base::win::RegKey;
 
 CopyRegKeyWorkItem::~CopyRegKeyWorkItem() {
 }
 
 CopyRegKeyWorkItem::CopyRegKeyWorkItem(HKEY predefined_root,
                                        const std::wstring& source_key_path,
-                                       const std::wstring& dest_key_path)
+                                       const std::wstring& dest_key_path,
+                                       CopyOverWriteOption overwrite_option)
     : predefined_root_(predefined_root),
       source_key_path_(source_key_path),
-      dest_key_path_(dest_key_path) {
+      dest_key_path_(dest_key_path),
+      overwrite_option_(overwrite_option),
+      cleared_destination_(false) {
   DCHECK(predefined_root);
   // It's a safe bet that we don't want to copy or overwrite one of the root
   // trees.
   DCHECK(!source_key_path.empty());
   DCHECK(!dest_key_path.empty());
+  DCHECK(overwrite_option == ALWAYS || overwrite_option == IF_NOT_PRESENT);
 }
 
 bool CopyRegKeyWorkItem::Do() {
   if (source_key_path_.empty() || dest_key_path_.empty())
     return false;
 
+  // Leave immediately if we're not supposed to overwrite an existing key and
+  // one is there.
+  if (overwrite_option_ == IF_NOT_PRESENT &&
+      RegKey(predefined_root_, dest_key_path_.c_str(),
+             KEY_QUERY_VALUE).Valid()) {
+    return true;
+  }
+
   RegistryKeyBackup backup;
   RegKey dest_key;
 
   // Only try to make a backup if we're not configured to ignore failures.
   if (!ignore_failure_) {
     if (!backup.Initialize(predefined_root_, dest_key_path_.c_str())) {
       LOG(ERROR) << "Failed to backup destination for registry key copy.";
       return false;
     }
   }
 
   // Delete the destination before attempting to copy.
   LONG result = SHDeleteKey(predefined_root_, dest_key_path_.c_str());
   if (result != ERROR_SUCCESS && result != ERROR_FILE_NOT_FOUND) {
     LOG(ERROR) << "Failed to delete key at " << dest_key_path_ << ", result: "
                << result;
   } else {
+    cleared_destination_ = true;
     // We've just modified the registry, so remember any backup we may have
     // made so that Rollback can take us back where we started.
     backup_.swap(backup);
     // Make the copy.
     result = dest_key.Create(predefined_root_, dest_key_path_.c_str(),
                              KEY_WRITE);
     if (result != ERROR_SUCCESS) {
       LOG(ERROR) << "Failed to open destination key at " << dest_key_path_
                  << ", result: " << result;
     } else {
@@ skipping 17 matching lines @@
     }
   }
 
   return ignore_failure_ ? true : (result == ERROR_SUCCESS);
 }
 
 void CopyRegKeyWorkItem::Rollback() {
   if (ignore_failure_)
     return;
 
-  // Delete anything in the key before restoring the backup in case someone else
-  // put new data in the key after Do().
-  LONG result = SHDeleteKey(predefined_root_, dest_key_path_.c_str());
-  if (result != ERROR_SUCCESS && result != ERROR_FILE_NOT_FOUND) {
-    LOG(ERROR) << "Failed to delete key at " << dest_key_path_
-               << " in rollback, result: " << result;
+  if (cleared_destination_) {
+    // Delete anything in the key before restoring the backup in case new data
+    // was written after Do().
+    LONG result = SHDeleteKey(predefined_root_, dest_key_path_.c_str());
+    if (result != ERROR_SUCCESS && result != ERROR_FILE_NOT_FOUND) {
+      LOG(ERROR) << "Failed to delete key at " << dest_key_path_
+                 << " in rollback, result: " << result;
+    }
+
+    // Restore the old contents.  The restoration takes on its default security
+    // attributes; any custom attributes are lost.
+    if (!backup_.WriteTo(predefined_root_, dest_key_path_.c_str()))
+      LOG(ERROR) << "Failed to restore key in rollback.";
   }
-
-  // Restore the old contents.  The restoration takes on its default security
-  // attributes; any custom attributes are lost.
-  if (!backup_.WriteTo(predefined_root_, dest_key_path_.c_str()))
-    LOG(ERROR) << "Failed to restore key in rollback.";
 }