An assert was being hit because WaitableEvent's dtor was calling CloseHandle on a handle that we already closed.

BUG=8070

Review URL: http://codereview.chromium.org/40195

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11078 0039d316-1c4b-4281-b951-d872f2087c98

base/waitable_event.h

@@ -56,6 +56,9 @@ class WaitableEvent {
   // created. This objects takes ownership of the HANDLE and will close it when
   // deleted.
   explicit WaitableEvent(HANDLE event_handle);
+
+  // Releases ownership of the handle from this object.
+  HANDLE Release();
 #endif
 
   // WARNING: Destroying a WaitableEvent while threads are waiting on it is not

base/waitable_event_win.cc

@@ -28,6 +28,12 @@ WaitableEvent::~WaitableEvent() {
   CloseHandle(handle_);
 }
 
+HANDLE WaitableEvent::Release() {
+  HANDLE rv = handle_;
+  handle_ = INVALID_HANDLE_VALUE;
+  return rv;
+}
+
 void WaitableEvent::Reset() {
   ResetEvent(handle_);
 }

chrome/common/child_process_host.cc

@@ -55,6 +55,10 @@ ChildProcessHost::~ChildProcessHost() {
   if (handle()) {
     watcher_.StopWatching();
     ProcessWatcher::EnsureProcessTerminated(handle());
+
+    // Above call took ownership, so don't want WaitableEvent to assert because
+    // the handle isn't valid anymore.
+    process_event_->Release();
   }
 }