sandbox/win: Fix warnings found by clang chromium-style plugin on Windows.

sandbox/win/src/win2k_threadpool.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 "sandbox/win/src/win2k_threadpool.h"
 
 #include "sandbox/win/src/win_utils.h"
 
 namespace sandbox {
 
+Win2kThreadPool::Win2kThreadPool() {
+  ::InitializeCriticalSection(&lock_);
+}
+
 bool Win2kThreadPool::RegisterWait(const void* cookie, HANDLE waitable_object,
                                    CrossCallIPCCallback callback,
                                    void* context) {
   if (0 == cookie) {
     return false;
   }
   HANDLE pool_object = NULL;
   // create a wait for a kernel object, with no timeout
   if (!::RegisterWaitForSingleObject(&pool_object, waitable_object, callback,
                                      context, INFINITE, WT_EXECUTEDEFAULT)) {
@@ skipping 30 matching lines @@
 }
 
 Win2kThreadPool::~Win2kThreadPool() {
   // Here we used to unregister all the pool wait handles. Now, following the
   // rest of the code we avoid lengthy or blocking calls given that the process
   // is being torn down.
   ::DeleteCriticalSection(&lock_);
 }
 
 }  // namespace sandbox