Clean Up Windows Thread Join Debug Code

base/threading/platform_thread_win.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 "base/threading/platform_thread.h"
 
 #include <stddef.h>
 
 #include "base/debug/alias.h"
 #include "base/debug/profiler.h"
@@ skipping 199 matching lines @@
   // shutdown.
   // Joining another thread may block the current thread for a long time, since
   // the thread referred to by |thread_handle| may still be running long-lived /
   // blocking tasks.
 #if 0
   base::ThreadRestrictions::AssertIOAllowed();
 #endif
 
   // Wait for the thread to exit.  It should already have terminated but make
   // sure this assumption is valid.
-  DWORD result = WaitForSingleObject(thread_handle.platform_handle(), INFINITE);
-  if (result != WAIT_OBJECT_0) {
-    // Debug info for bug 127931.
-    DWORD error = GetLastError();
-    debug::Alias(&error);
-    debug::Alias(&result);
-    CHECK(false);
-  }
-
+  CHECK_EQ(WAIT_OBJECT_0,

[danakj, 2016/06/10 17:38:25]

Can you make it a DCHECK also?

[danakj, 2016/06/10 17:41:06]

I see you made a comment about this is bad so we should CHECK. It was a CHECK
because it was tracking down a bug, which makes sense. Once a bug is resolved, I
think we should make it back into a DCHECK.

[robliao, 2016/06/10 18:06:42]

We CHECK on the equivalent call in POSIX.
https://cs.chromium.org/chromium/src/base/threading/platform_thread_posix.cc?...

So it seemed reasonable to keep the CHECK here. A failure to join could mean a
thread is now running around unexpectedly, which could cause a crash later down
the line.

[danakj, 2016/06/10 22:03:32]

Oh, okay thanks for the pointer. LGTM

+           WaitForSingleObject(thread_handle.platform_handle(), INFINITE));
   CloseHandle(thread_handle.platform_handle());
 }
 
 // static
 void PlatformThread::Detach(PlatformThreadHandle thread_handle) {
   CloseHandle(thread_handle.platform_handle());
 }
 
 // static
 void PlatformThread::SetCurrentThreadPriority(ThreadPriority priority) {
@@ skipping 41 matching lines @@
       return ThreadPriority::REALTIME_AUDIO;
     case THREAD_PRIORITY_ERROR_RETURN:
       DPCHECK(false) << "GetThreadPriority error";  // Falls through.
     default:
       NOTREACHED() << "Unexpected priority: " << priority;
       return ThreadPriority::NORMAL;
   }
 }
 
 }  // namespace base