Revert of Remove raw handles from base::win::RegKey (patchset #6 id:330001 of https://codereview.chromium.org/632833002/)

Reason for revert:
Causing base_unittests failures on XP Tests (1)

Original issue's description:
> Remove raw handles from base::win::RegKey
>
> BUG=419210, 423634
> R=cpu@chromium.org, eroman@chromium.org, sky@chromium.org
>
> Committed: https://crrev.com/1aa0fa75b65f403e08ae0f3f2fcb053c02cd9ef2
> Cr-Commit-Position: refs/heads/master@{#299737}

TBR=cpu@chromium.org,eroman@chromium.org,jam@chromium.org,rvargas@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=419210, 423634

Review URL: https://codereview.chromium.org/652903005

Cr-Commit-Position: refs/heads/master@{#299828}

8 files changed, 171 insertions, 204 deletions

diff --git a/base/win/registry.cc b/base/win/registry.cc
index 8e7083f..e8fb892 100644
--- a/base/win/registry.cc
+++ b/base/win/registry.cc
@@ -34,74 +34,23 @@ const REGSAM kWow64AccessMask = KEY_WOW64_32KEY | KEY_WOW64_64KEY;
 
 }  // namespace
 
-// Watches for modifications to a key.
-class RegKey::Watcher : public ObjectWatcher::Delegate {
- public:
-  explicit Watcher(RegKey* owner) : owner_(owner) {}
-  ~Watcher() {}
-
-  bool StartWatching(HKEY key, const ChangeCallback& callback);
-
-  // Implementation of ObjectWatcher::Delegate.
-  void OnObjectSignaled(HANDLE object) override {
-    DCHECK(watch_event_.IsValid() && watch_event_.Get() == object);
-    ChangeCallback callback = callback_;
-    callback_.Reset();
-    callback.Run();
-  }
-
- private:
-  RegKey* owner_;
-  ScopedHandle watch_event_;
-  ObjectWatcher object_watcher_;
-  ChangeCallback callback_;
-  DISALLOW_COPY_AND_ASSIGN(Watcher);
-};
-
-bool RegKey::Watcher::StartWatching(HKEY key, const ChangeCallback& callback) {
-  DCHECK(key);
-  DCHECK(callback_.is_null());
-  if (GetVersion() < VERSION_VISTA) {
-    // It is an error to register multiple times before Vista.
-    if (watch_event_.IsValid()) {
-      callback_ = callback;
-      return true;
-    }
-  }
-
-  if (!watch_event_.IsValid())
-    watch_event_.Set(CreateEvent(NULL, TRUE, FALSE, NULL));
-
-  if (!watch_event_.IsValid())
-    return false;
-
-  DWORD filter = REG_NOTIFY_CHANGE_NAME |
-                 REG_NOTIFY_CHANGE_ATTRIBUTES |
-                 REG_NOTIFY_CHANGE_LAST_SET |
-                 REG_NOTIFY_CHANGE_SECURITY;
-
-  // Watch the registry key for a change of value.
-  LONG result = RegNotifyChangeKeyValue(key, TRUE, filter, watch_event_.Get(),
-                                        TRUE);
-  if (result != ERROR_SUCCESS) {
-    watch_event_.Close();
-    return false;
-  }
-
-  callback_ = callback;
-  return object_watcher_.StartWatching(watch_event_.Get(), this);
-}
-
 // RegKey ----------------------------------------------------------------------
 
-RegKey::RegKey() : key_(NULL), wow64access_(0) {
+RegKey::RegKey()
+    : key_(NULL),
+      watch_event_(0),
+      wow64access_(0) {
 }
 
-RegKey::RegKey(HKEY key) : key_(key), wow64access_(0) {
+RegKey::RegKey(HKEY key)
+    : key_(key),
+      watch_event_(0),
+      wow64access_(0) {
 }
 
 RegKey::RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access)
     : key_(NULL),
+      watch_event_(0),
       wow64access_(0) {
   if (rootkey) {
     if (access & (KEY_SET_VALUE | KEY_CREATE_SUB_KEY | KEY_CREATE_LINK))
@@ -201,6 +150,7 @@ LONG RegKey::OpenKey(const wchar_t* relative_key_name, REGSAM access) {
 }
 
 void RegKey::Close() {
+  StopWatching();
   if (key_) {
     ::RegCloseKey(key_);
     key_ = NULL;
@@ -218,6 +168,7 @@ void RegKey::Set(HKEY key) {
 
 HKEY RegKey::Take() {
   DCHECK(wow64access_ == 0);
+  StopWatching();
   HKEY key = key_;
   key_ = NULL;
   return key;
@@ -416,14 +367,44 @@ LONG RegKey::WriteValue(const wchar_t* name,
   return result;
 }
 
-bool RegKey::StartWatching(const ChangeCallback& callback) {
-  if (!key_watcher_)
-    key_watcher_.reset(new Watcher(this));
+LONG RegKey::StartWatching() {
+  DCHECK(key_);
+  if (!watch_event_)
+    watch_event_ = CreateEvent(NULL, TRUE, FALSE, NULL);
 
-  if (!key_watcher_.get()->StartWatching(key_, callback))
-    return false;
+  DWORD filter = REG_NOTIFY_CHANGE_NAME |
+                 REG_NOTIFY_CHANGE_ATTRIBUTES |
+                 REG_NOTIFY_CHANGE_LAST_SET |
+                 REG_NOTIFY_CHANGE_SECURITY;
 
-  return true;
+  // Watch the registry key for a change of value.
+  LONG result = RegNotifyChangeKeyValue(key_, TRUE, filter, watch_event_, TRUE);
+  if (result != ERROR_SUCCESS) {
+    CloseHandle(watch_event_);
+    watch_event_ = 0;
+  }
+
+  return result;
+}
+
+bool RegKey::HasChanged() {
+  if (watch_event_) {
+    if (WaitForSingleObject(watch_event_, 0) == WAIT_OBJECT_0) {
+      StartWatching();
+      return true;
+    }
+  }
+  return false;
+}
+
+LONG RegKey::StopWatching() {
+  LONG result = ERROR_INVALID_HANDLE;
+  if (watch_event_) {
+    CloseHandle(watch_event_);
+    watch_event_ = 0;
+    result = ERROR_SUCCESS;
+  }
+  return result;
 }
 
 // static
diff --git a/base/win/registry.h b/base/win/registry.h
index c3e015b..e5524b8 100644
--- a/base/win/registry.h
+++ b/base/win/registry.h
@@ -12,8 +12,6 @@
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/stl_util.h"
-#include "base/win/object_watcher.h"
-#include "base/win/scoped_handle.h"
 
 namespace base {
 namespace win {
@@ -27,9 +25,6 @@ namespace win {
 // are not touched in case of failure.
 class BASE_EXPORT RegKey {
  public:
-  // Called from the MessageLoop when the key changes.
-  typedef base::Callback<void()> ChangeCallback;
-
   RegKey();
   explicit RegKey(HKEY key);
   RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access);
@@ -125,16 +120,22 @@ class BASE_EXPORT RegKey {
 
   // Starts watching the key to see if any of its values have changed.
   // The key must have been opened with the KEY_NOTIFY access privilege.
-  // Returns true on success.
-  // To stop watching, delete this RegKey object. To continue watching the
-  // object after the callback is invoked, call StartWatching again.
-  bool StartWatching(const ChangeCallback& callback);
+  LONG StartWatching();
+
+  // If StartWatching hasn't been called, always returns false.
+  // Otherwise, returns true if anything under the key has changed.
+  // This can't be const because the |watch_event_| may be refreshed.
+  bool HasChanged();
+
+  // Will automatically be called by destructor if not manually called
+  // beforehand.  Returns true if it was watching, false otherwise.
+  LONG StopWatching();
 
+  inline bool IsWatching() const { return watch_event_ != 0; }
+  HANDLE watch_event() const { return watch_event_; }
   HKEY Handle() const { return key_; }
 
  private:
-  class Watcher;
-
   // Calls RegDeleteKeyEx on supported platforms, alternatively falls back to
   // RegDeleteKey.
   static LONG RegDeleteKeyExWrapper(HKEY hKey,
@@ -146,10 +147,9 @@ class BASE_EXPORT RegKey {
   static LONG RegDelRecurse(HKEY root_key,
                             const std::wstring& name,
                             REGSAM access);
-
   HKEY key_;  // The registry key being iterated.
+  HANDLE watch_event_;
   REGSAM wow64access_;
-  scoped_ptr<Watcher> key_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(RegKey);
 };
diff --git a/base/win/registry_unittest.cc b/base/win/registry_unittest.cc
index 6548474..d2610ef 100644
--- a/base/win/registry_unittest.cc
+++ b/base/win/registry_unittest.cc
@@ -7,10 +7,7 @@
 #include <cstring>
 #include <vector>
 
-#include "base/bind.h"
 #include "base/compiler_specific.h"
-#include "base/message_loop/message_loop.h"
-#include "base/run_loop.h"
 #include "base/stl_util.h"
 #include "base/win/windows_version.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -352,68 +349,6 @@ TEST_F(RegistryTest, OpenSubKey) {
   ASSERT_EQ(ERROR_SUCCESS, key.DeleteKey(L"foo"));
 }
 
-class TestChangeDelegate {
- public:
-   TestChangeDelegate() : called_(false) {}
-   ~TestChangeDelegate() {}
-
-   void OnKeyChanged() {
-     MessageLoop::current()->QuitWhenIdle();
-     called_ = true;
-   }
-
-   bool WasCalled() {
-     bool was_called = called_;
-     called_ = false;
-     return was_called;
-   }
-
- private:
-  bool called_;
-};
-
-TEST_F(RegistryTest, ChangeCallback) {
-  RegKey key;
-  TestChangeDelegate delegate;
-  MessageLoop message_loop;
-
-  std::wstring foo_key(kRootKey);
-  foo_key += L"\\Foo";
-  ASSERT_EQ(ERROR_SUCCESS, key.Create(HKEY_CURRENT_USER, foo_key.c_str(),
-                                      KEY_READ));
-
-  ASSERT_TRUE(key.StartWatching(Bind(&TestChangeDelegate::OnKeyChanged,
-                                     Unretained(&delegate))));
-  EXPECT_FALSE(delegate.WasCalled());
-
-  // Make some change.
-  RegKey key2;
-  ASSERT_EQ(ERROR_SUCCESS, key2.Open(HKEY_CURRENT_USER, foo_key.c_str(),
-                                      KEY_READ | KEY_SET_VALUE));
-  ASSERT_TRUE(key2.Valid());
-  EXPECT_EQ(ERROR_SUCCESS, key2.WriteValue(L"name", L"data"));
-
-  // Allow delivery of the notification.
-  EXPECT_FALSE(delegate.WasCalled());
-  base::RunLoop().Run();
-
-  ASSERT_TRUE(delegate.WasCalled());
-  EXPECT_FALSE(delegate.WasCalled());
-
-  ASSERT_TRUE(key.StartWatching(Bind(&TestChangeDelegate::OnKeyChanged,
-                                     Unretained(&delegate))));
-
-  // Change something else.
-  EXPECT_EQ(ERROR_SUCCESS, key2.WriteValue(L"name2", L"data2"));
-  base::RunLoop().Run();
-  ASSERT_TRUE(delegate.WasCalled());
-
-  ASSERT_TRUE(key.StartWatching(Bind(&TestChangeDelegate::OnKeyChanged,
-                                     Unretained(&delegate))));
-  base::RunLoop().RunUntilIdle();
-  EXPECT_FALSE(delegate.WasCalled());
-}
-
 }  // namespace
 
 }  // namespace win
diff --git a/content/browser/plugin_service_impl.cc b/content/browser/plugin_service_impl.cc
index d19f686..1b7ad76 100644
--- a/content/browser/plugin_service_impl.cc
+++ b/content/browser/plugin_service_impl.cc
@@ -157,6 +157,15 @@ PluginServiceImpl::PluginServiceImpl()
 }
 
 PluginServiceImpl::~PluginServiceImpl() {
+#if defined(OS_WIN)
+  // Release the events since they're owned by RegKey, not WaitableEvent.
+  hkcu_watcher_.StopWatching();
+  hklm_watcher_.StopWatching();
+  if (hkcu_event_)
+    hkcu_event_->Release();
+  if (hklm_event_)
+    hklm_event_->Release();
+#endif
   // Make sure no plugin channel requests have been leaked.
   DCHECK(pending_plugin_clients_.empty());
 }
@@ -191,18 +200,24 @@ void PluginServiceImpl::StartWatchingPlugins() {
   if (hkcu_key_.Create(HKEY_CURRENT_USER,
                        kRegistryMozillaPlugins,
                        KEY_NOTIFY) == ERROR_SUCCESS) {
-    base::win::RegKey::ChangeCallback callback =
-        base::Bind(&PluginServiceImpl::OnKeyChanged, base::Unretained(this),
-                   base::Unretained(&hkcu_key_));
-    hkcu_key_.StartWatching(callback);
+    if (hkcu_key_.StartWatching() == ERROR_SUCCESS) {
+      hkcu_event_.reset(new base::WaitableEvent(hkcu_key_.watch_event()));
+      base::WaitableEventWatcher::EventCallback callback =
+            base::Bind(&PluginServiceImpl::OnWaitableEventSignaled,
+                       base::Unretained(this));
+      hkcu_watcher_.StartWatching(hkcu_event_.get(), callback);
+    }
   }
   if (hklm_key_.Create(HKEY_LOCAL_MACHINE,
                        kRegistryMozillaPlugins,
                        KEY_NOTIFY) == ERROR_SUCCESS) {
-    base::win::RegKey::ChangeCallback callback =
-        base::Bind(&PluginServiceImpl::OnKeyChanged, base::Unretained(this),
-                   base::Unretained(&hkcu_key_));
-    hklm_key_.StartWatching(callback);
+    if (hklm_key_.StartWatching() == ERROR_SUCCESS) {
+      hklm_event_.reset(new base::WaitableEvent(hklm_key_.watch_event()));
+      base::WaitableEventWatcher::EventCallback callback =
+            base::Bind(&PluginServiceImpl::OnWaitableEventSignaled,
+                       base::Unretained(this));
+      hklm_watcher_.StartWatching(hklm_event_.get(), callback);
+    }
   }
 #endif
 #if defined(OS_POSIX) && !defined(OS_OPENBSD) && !defined(OS_ANDROID)
@@ -627,16 +642,22 @@ void PluginServiceImpl::GetPluginsOnIOThread(
 }
 #endif
 
+void PluginServiceImpl::OnWaitableEventSignaled(
+    base::WaitableEvent* waitable_event) {
 #if defined(OS_WIN)
-void PluginServiceImpl::OnKeyChanged(base::win::RegKey* key) {
-  key->StartWatching(base::Bind(&PluginServiceImpl::OnKeyChanged,
-                                base::Unretained(this),
-                                base::Unretained(&hkcu_key_)));
+  if (waitable_event == hkcu_event_) {
+    hkcu_key_.StartWatching();
+  } else {
+    hklm_key_.StartWatching();
+  }
 
   PluginList::Singleton()->RefreshPlugins();
   PurgePluginListCache(NULL, false);
-}
+#else
+  // This event should only get signaled on a Windows machine.
+  NOTREACHED();
 #endif  // defined(OS_WIN)
+}
 
 void PluginServiceImpl::RegisterPepperPlugins() {
   ComputePepperPluginList(&ppapi_plugins_);
diff --git a/content/browser/plugin_service_impl.h b/content/browser/plugin_service_impl.h
index 0b5cc5f..a0353e5 100644
--- a/content/browser/plugin_service_impl.h
+++ b/content/browser/plugin_service_impl.h
@@ -166,9 +166,7 @@ class CONTENT_EXPORT PluginServiceImpl
   PluginServiceImpl();
   virtual ~PluginServiceImpl();
 
-#if defined(OS_WIN)
-  void OnKeyChanged(base::win::RegKey* key);
-#endif
+  void OnWaitableEventSignaled(base::WaitableEvent* waitable_event);
 
   // Returns the plugin process host corresponding to the plugin process that
   // has been started by this service. Returns NULL if no process has been
@@ -226,6 +224,10 @@ class CONTENT_EXPORT PluginServiceImpl
   // Registry keys for getting notifications when new plugins are installed.
   base::win::RegKey hkcu_key_;
   base::win::RegKey hklm_key_;
+  scoped_ptr<base::WaitableEvent> hkcu_event_;
+  scoped_ptr<base::WaitableEvent> hklm_event_;
+  base::WaitableEventWatcher hkcu_watcher_;
+  base::WaitableEventWatcher hklm_watcher_;
 #endif
 
 #if defined(OS_POSIX) && !defined(OS_OPENBSD) && !defined(OS_ANDROID)
diff --git a/net/dns/dns_config_service_win.cc b/net/dns/dns_config_service_win.cc
index ddb8a4c..dd3ee3d 100644
--- a/net/dns/dns_config_service_win.cc
+++ b/net/dns/dns_config_service_win.cc
@@ -23,8 +23,8 @@
 #include "base/threading/non_thread_safe.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
+#include "base/win/object_watcher.h"
 #include "base/win/registry.h"
-#include "base/win/scoped_handle.h"
 #include "base/win/windows_version.h"
 #include "net/base/net_util.h"
 #include "net/base/network_change_notifier.h"
@@ -292,7 +292,8 @@ HostsParseWinResult AddLocalhostEntries(DnsHosts* hosts) {
 }
 
 // Watches a single registry key for changes.
-class RegistryWatcher : public base::NonThreadSafe {
+class RegistryWatcher : public base::win::ObjectWatcher::Delegate,
+                        public base::NonThreadSafe {
  public:
   typedef base::Callback<void(bool succeeded)> CallbackType;
   RegistryWatcher() {}
@@ -304,31 +305,35 @@ class RegistryWatcher : public base::NonThreadSafe {
     callback_ = callback;
     if (key_.Open(HKEY_LOCAL_MACHINE, key, KEY_NOTIFY) != ERROR_SUCCESS)
       return false;
-
-    return key_.StartWatching(base::Bind(&RegistryWatcher::OnObjectSignaled,
-                                         base::Unretained(this)));
+    if (key_.StartWatching() != ERROR_SUCCESS)
+      return false;
+    if (!watcher_.StartWatching(key_.watch_event(), this))
+      return false;
+    return true;
   }
 
-  void OnObjectSignaled() {
+  virtual void OnObjectSignaled(HANDLE object) override {
     // TODO(vadimt): Remove ScopedProfile below once crbug.com/418183 is fixed.
     tracked_objects::ScopedProfile tracking_profile(
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "RegistryWatcher_OnObjectSignaled"));
 
     DCHECK(CalledOnValidThread());
-    DCHECK(!callback_.is_null());
-    if (key_.StartWatching(base::Bind(&RegistryWatcher::OnObjectSignaled,
-                                      base::Unretained(this)))) {
-      callback_.Run(true);
-    } else {
+    bool succeeded = (key_.StartWatching() == ERROR_SUCCESS) &&
+                      watcher_.StartWatching(key_.watch_event(), this);
+    if (!succeeded && key_.Valid()) {
+      watcher_.StopWatching();
+      key_.StopWatching();
       key_.Close();
-      callback_.Run(false);
     }
+    if (!callback_.is_null())
+      callback_.Run(succeeded);
   }
 
  private:
   CallbackType callback_;
   base::win::RegKey key_;
+  base::win::ObjectWatcher watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(RegistryWatcher);
 };
@@ -735,8 +740,9 @@ bool DnsConfigServiceWin::StartWatching() {
 
 void DnsConfigServiceWin::OnConfigChanged(bool succeeded) {
   InvalidateConfig();
-  config_reader_->WorkNow();
-  if (!succeeded) {
+  if (succeeded) {
+    config_reader_->WorkNow();
+  } else {
     LOG(ERROR) << "DNS config watch failed.";
     set_watch_failed(true);
     UMA_HISTOGRAM_ENUMERATION("AsyncDNS.WatchStatus",
diff --git a/net/proxy/proxy_config_service_win.cc b/net/proxy/proxy_config_service_win.cc
index dba1d9b..32553db 100644
--- a/net/proxy/proxy_config_service_win.cc
+++ b/net/proxy/proxy_config_service_win.cc
@@ -7,8 +7,6 @@
 #include <windows.h>
 #include <winhttp.h>
 
-#include "base/bind.h"
-#include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/profiler/scoped_profile.h"
@@ -18,7 +16,6 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/win/registry.h"
-#include "base/win/scoped_handle.h"
 #include "net/base/net_errors.h"
 #include "net/proxy/proxy_config.h"
 
@@ -41,6 +38,36 @@ void FreeIEConfig(WINHTTP_CURRENT_USER_IE_PROXY_CONFIG* ie_config) {
 
 }  // namespace
 
+// RegKey and ObjectWatcher pair.
+class ProxyConfigServiceWin::KeyEntry {
+ public:
+  bool StartWatching(base::win::ObjectWatcher::Delegate* delegate) {
+    // Try to create a watch event for the registry key (which watches the
+    // sibling tree as well).
+    if (key_.StartWatching() != ERROR_SUCCESS)
+      return false;
+
+    // Now setup an ObjectWatcher for this event, so we get OnObjectSignaled()
+    // invoked on this message loop once it is signalled.
+    if (!watcher_.StartWatching(key_.watch_event(), delegate))
+      return false;
+
+    return true;
+  }
+
+  bool CreateRegKey(HKEY rootkey, const wchar_t* subkey) {
+    return key_.Create(rootkey, subkey, KEY_NOTIFY) == ERROR_SUCCESS;
+  }
+
+  HANDLE watch_event() const {
+    return key_.watch_event();
+  }
+
+ private:
+  base::win::RegKey key_;
+  base::win::ObjectWatcher watcher_;
+};
+
 ProxyConfigServiceWin::ProxyConfigServiceWin()
     : PollingProxyConfigService(
           base::TimeDelta::FromSeconds(kPollIntervalSec),
@@ -98,38 +125,35 @@ void ProxyConfigServiceWin::StartWatchingRegistryForChanges() {
 
 bool ProxyConfigServiceWin::AddKeyToWatchList(HKEY rootkey,
                                               const wchar_t* subkey) {
-  scoped_ptr<base::win::RegKey> key(new base::win::RegKey);
-  if (key->Create(rootkey, subkey, KEY_NOTIFY) != ERROR_SUCCESS)
+  scoped_ptr<KeyEntry> entry(new KeyEntry);
+  if (!entry->CreateRegKey(rootkey, subkey))
     return false;
 
-  if (!key->StartWatching(base::Bind(&ProxyConfigServiceWin::OnObjectSignaled,
-                                     base::Unretained(this),
-                                     base::Unretained(key.get())))) {
+  if (!entry->StartWatching(this))
     return false;
-  }
 
-  keys_to_watch_.push_back(key.release());
+  keys_to_watch_.push_back(entry.release());
   return true;
 }
 
-void ProxyConfigServiceWin::OnObjectSignaled(base::win::RegKey* key) {
+void ProxyConfigServiceWin::OnObjectSignaled(HANDLE object) {
   // TODO(vadimt): Remove ScopedProfile below once crbug.com/418183 is fixed.
   tracked_objects::ScopedProfile tracking_profile(
       FROM_HERE_WITH_EXPLICIT_FUNCTION(
           "ProxyConfigServiceWin_OnObjectSignaled"));
 
   // Figure out which registry key signalled this change.
-  RegKeyList::iterator it =
-      std::find(keys_to_watch_.begin(), keys_to_watch_.end(), key);
+  KeyEntryList::iterator it;
+  for (it = keys_to_watch_.begin(); it != keys_to_watch_.end(); ++it) {
+    if ((*it)->watch_event() == object)
+      break;
+  }
+
   DCHECK(it != keys_to_watch_.end());
 
   // Keep watching the registry key.
-  if (!key->StartWatching(base::Bind(&ProxyConfigServiceWin::OnObjectSignaled,
-                                     base::Unretained(this),
-                                     base::Unretained(key)))) {
-    delete *it;
+  if (!(*it)->StartWatching(this))
     keys_to_watch_.erase(it);
-  }
 
   // Have the PollingProxyConfigService test for changes.
   CheckForChangesNow();
diff --git a/net/proxy/proxy_config_service_win.h b/net/proxy/proxy_config_service_win.h
index 52c3895..62f1f12 100644
--- a/net/proxy/proxy_config_service_win.h
+++ b/net/proxy/proxy_config_service_win.h
@@ -12,14 +12,9 @@
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
+#include "base/win/object_watcher.h"
 #include "net/proxy/polling_proxy_config_service.h"
 
-namespace base {
-namespace win {
-class RegKey;
-}
-}  // namespace base.
-
 namespace net {
 
 // Implementation of ProxyConfigService that retrieves the system proxy
@@ -45,7 +40,8 @@ namespace net {
 // change, or in case we got it wrong (and are not checking all possible
 // registry dependencies).
 class NET_EXPORT_PRIVATE ProxyConfigServiceWin
-    : public PollingProxyConfigService {
+    : public PollingProxyConfigService,
+      public base::win::ObjectWatcher::Delegate {
  public:
   ProxyConfigServiceWin();
   virtual ~ProxyConfigServiceWin();
@@ -55,17 +51,19 @@ class NET_EXPORT_PRIVATE ProxyConfigServiceWin
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ProxyConfigServiceWinTest, SetFromIEConfig);
-  typedef std::vector<base::win::RegKey*> RegKeyList;
+  class KeyEntry;
+  typedef std::vector<KeyEntry*> KeyEntryList;
 
   // Registers change observers on the registry keys relating to proxy settings.
   void StartWatchingRegistryForChanges();
 
-  // Creates a new key and appends it to |keys_to_watch_|. If the key fails to
-  // be created, it is not appended to the list and we return false.
+  // Creates a new KeyEntry and appends it to |keys_to_watch_|. If the key
+  // fails to be created, it is not appended to the list and we return false.
   bool AddKeyToWatchList(HKEY rootkey, const wchar_t* subkey);
 
+  // ObjectWatcher::Delegate methods:
   // This is called whenever one of the registry keys we are watching change.
-  void OnObjectSignaled(base::win::RegKey* key);
+  virtual void OnObjectSignaled(HANDLE object) override;
 
   static void GetCurrentProxyConfig(ProxyConfig* config);
 
@@ -74,7 +72,7 @@ class NET_EXPORT_PRIVATE ProxyConfigServiceWin
       ProxyConfig* config,
       const WINHTTP_CURRENT_USER_IE_PROXY_CONFIG& ie_config);
 
-  RegKeyList keys_to_watch_;
+  KeyEntryList keys_to_watch_;
 };
 
 }  // namespace net