Cleanup in ProcessSingleton.

chrome/browser/process_singleton_win.cc

Index: chrome/browser/process_singleton_win.cc
diff --git a/chrome/browser/process_singleton_win.cc b/chrome/browser/process_singleton_win.cc
index e92a5f2cbe655dd85f82fbeacc2b88a26724ed03..d71e67cbe1dcdb0b26f11911960ddea5c2aeb489 100644
--- a/chrome/browser/process_singleton_win.cc
+++ b/chrome/browser/process_singleton_win.cc
@@ -102,18 +102,37 @@ ProcessSingleton::ProcessSingleton(const FilePath& user_data_dir)
     remote_window_ = FindWindowEx(HWND_MESSAGE, NULL,
                                   chrome::kMessageWindowClass,
                                   user_data_dir.value().c_str());
-    if (!remote_window_)
-      Create();
+    if (!remote_window_) {
+      HINSTANCE hinst =
+          base::GetModuleFromAddress(ProcessSingleton::WndProcStatic);
+
+      WNDCLASSEX wc = {0};
+      wc.cbSize = sizeof(wc);
+      wc.lpfnWndProc =
+          base::win::WrappedWindowProc<ProcessSingleton::WndProcStatic>;
+      wc.hInstance = hinst;
+      wc.lpszClassName = chrome::kMessageWindowClass;
+      ATOM clazz = RegisterClassEx(&wc);
+      DCHECK(clazz);
+
+      FilePath user_data_dir;
+      PathService::Get(chrome::DIR_USER_DATA, &user_data_dir);
+
+      // Set the window's title to the path of our user data directory so other
+      // Chrome instances can decide if they should forward to us or not.
+      window_ = CreateWindow(chrome::kMessageWindowClass,
+                             user_data_dir.value().c_str(),
+                             0, 0, 0, 0, 0, HWND_MESSAGE, 0, hinst, 0);
+      ui::CheckWindowCreated(window_);
+      ui::SetWindowUserData(window_, this);
+    }
     BOOL success = ReleaseMutex(only_me);
     DCHECK(success) << "GetLastError = " << GetLastError();
   }
 }
 
 ProcessSingleton::~ProcessSingleton() {
-  if (window_) {
-    DestroyWindow(window_);
-    UnregisterClass(chrome::kMessageWindowClass, GetModuleHandle(NULL));
-  }
+  Cleanup();
 }
 
 ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcess() {
@@ -197,42 +216,29 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessOrCreate() {
   NotifyResult result = NotifyOtherProcess();
   if (result != PROCESS_NONE)
     return result;
-  return Create() ? PROCESS_NONE : PROFILE_IN_USE;
+  return window_ ? PROCESS_NONE : PROFILE_IN_USE;
 }
 
-// For windows, there is no need to call Create() since the call is made in
+// On Windows, there is no need to call Create() since the call is made in
 // the constructor but to avoid having more platform specific code in
 // browser_main.cc we tolerate a second call which will do nothing.
 bool ProcessSingleton::Create() {
   DCHECK(!remote_window_);
-  if (window_)
-    return true;
-
-  HINSTANCE hinst = GetModuleHandle(NULL);
-
-  WNDCLASSEX wc = {0};
-  wc.cbSize = sizeof(wc);
-  wc.lpfnWndProc =
-      base::win::WrappedWindowProc<ProcessSingleton::WndProcStatic>;
-  wc.hInstance = hinst;
-  wc.lpszClassName = chrome::kMessageWindowClass;
-  ATOM clazz = RegisterClassEx(&wc);
-  DCHECK(clazz);
-
-  FilePath user_data_dir;
-  PathService::Get(chrome::DIR_USER_DATA, &user_data_dir);
-
-  // Set the window's title to the path of our user data directory so other
-  // Chrome instances can decide if they should forward to us or not.
-  window_ = CreateWindow(chrome::kMessageWindowClass,
-                         user_data_dir.value().c_str(),
-                         0, 0, 0, 0, 0, HWND_MESSAGE, 0, hinst, 0);
-  ui::CheckWindowCreated(window_);
-  ui::SetWindowUserData(window_, this);
-  return true;
+  return window_ != NULL;
 }
 
 void ProcessSingleton::Cleanup() {
+  // Window classes registered by DLLs are not cleaned up automatically on
+  // process exit, so we must unregister at the earliest chance possible.
+  // During the fast shutdown sequence, ProcessSingleton::Cleanup() is
+  // called if our process was the first to start.  Therefore we try cleaning
+  // up here, and again in the destructor if needed to catch as many cases
+  // as possible.
+  if (window_) {
+    DestroyWindow(window_);
+    UnregisterClass(chrome::kMessageWindowClass, GetModuleHandle(NULL));
+    window_ = NULL;
+  }
 }
 
 LRESULT ProcessSingleton::OnCopyData(HWND hwnd, const COPYDATASTRUCT* cds) {