Properly "handle" MOJO_RESULT_BUSY in a few flaces.

mojo/public/cpp/system/wait.h

 // Copyright 2016 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.
 
 #ifndef MOJO_PUBLIC_CPP_SYSTEM_WAIT_H_
 #define MOJO_PUBLIC_CPP_SYSTEM_WAIT_H_
 
 #include <stdint.h>
 
 #include <cstddef>
@@ skipping 26 matching lines @@
   // A valid handle index is always returned if |WaitMany()| succeeds, but may
   // or may not be returned if |WaitMany()| returns an error. Use this helper
   // function to check if |index| is a valid index into the handle array.
   bool IsIndexValid() const { return index != kInvalidWaitManyIndexValue; }
 
   // The |signals_states| array is always returned by |WaitMany()| on success,
   // but may or may not be returned if |WaitMany()| returns an error. Use this
   // helper function to check if |signals_states| holds valid data.
   bool AreSignalsStatesValid() const {
     return result != MOJO_RESULT_INVALID_ARGUMENT &&
-           result != MOJO_RESULT_RESOURCE_EXHAUSTED;
+           result != MOJO_RESULT_RESOURCE_EXHAUSTED &&
+           result != MOJO_RESULT_BUSY;
   }
 
   MojoResult result;
   uint32_t index;
 };
 
 // |HandleVectorType| and |FlagsVectorType| should be similar enough to
 // |std::vector<Handle>| and |std::vector<MojoHandleSignals>|, respectively:
 //  - They should have a (const) |size()| method that returns an unsigned type.
 //  - They must provide contiguous storage, with access via (const) reference to
@@ skipping 51 matching lines @@
   const MojoHandleSignals& first_signals = signals[0];
   MojoResult result = MojoWaitMany(
       reinterpret_cast<const MojoHandle*>(&first_handle), &first_signals,
       static_cast<uint32_t>(handles.size()), deadline, &result_index, nullptr);
   return WaitManyResult(result, result_index);
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_SYSTEM_WAIT_H_