[mojo-edk] Fix lifetime management of rewritten Windows HANDLEs

mojo/edk/embedder/platform_handle.cc

 // Copyright 2013 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 "mojo/edk/embedder/platform_handle.h"
 
 #include "build/build_config.h"
 #if defined(OS_POSIX)
 #include <unistd.h>
 #elif defined(OS_WIN)
@@ skipping 18 matching lines @@
     handle = -1;
   }
 #if defined(OS_MACOSX) && !defined(OS_IOS)
   else if (type == Type::MACH) {
     kern_return_t rv = mach_port_deallocate(mach_task_self(), port);
     DPCHECK(rv == KERN_SUCCESS);
     port = MACH_PORT_NULL;
   }
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 #elif defined(OS_WIN)
+  if (owning_process != base::GetCurrentProcessHandle()) {
+    // This handle may have been duplicated to a new target process but not yet
+    // sent there. In this case CloseHandle should NOT be called. From MSDN
+    // documentation for DuplicateHandle[1]:
+    //
+    //    Normally the target process closes a duplicated handle when that
+    //    process is finished using the handle. To close a duplicated handle
+    //    from the source process, call DuplicateHandle with the following
+    //    parameters:
+    //
+    //    * Set hSourceProcessHandle to the target process from the
+    //      call that created the handle.
+    //    * Set hSourceHandle to the duplicated handle to close.
+    //    * Set lpTargetHandle to NULL.
+    //    * Set dwOptions to DUPLICATE_CLOSE_SOURCE.
+    //
+    // [1] https://msdn.microsoft.com/en-us/library/windows/desktop/ms724251
+    //
+    // NOTE: It's possible for this operation to fail if the owning process
+    // was terminated or is in the process of being terminated. Either way,
+    // there is nothing we can reasonably do about failure, so we ignore it.
+    DuplicateHandle(owning_process, handle, NULL, &handle, 0, FALSE,
+                    DUPLICATE_CLOSE_SOURCE);
+    return;
+  }
+
   bool success = !!CloseHandle(handle);
   DPCHECK(success);
   handle = INVALID_HANDLE_VALUE;
 #else
 #error "Platform not yet supported."
 #endif
 }
 
 }  // namespace edk
 }  // namespace mojo