Properly "handle" MOJO_RESULT_BUSY in a few flaces.

mojo/message_pump/message_pump_mojo.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/message_pump/message_pump_mojo.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/alias.h"
@@ skipping 187 matching lines @@
                  run_state_->wait_state->handles[wait_many_result.index]) !=
              handlers_.end());
       WillSignalHandler();
       handlers_[run_state_->wait_state->handles[wait_many_result.index]]
           .handler->OnHandleReady(
               run_state_->wait_state->handles[wait_many_result.index]);
       DidSignalHandler();
     }
   } else {
     switch (result) {
-      case MOJO_RESULT_CANCELLED:
       case MOJO_RESULT_FAILED_PRECONDITION:
         RemoveInvalidHandle(*run_state_->wait_state, result,
                             wait_many_result.index);
         break;
       case MOJO_RESULT_DEADLINE_EXCEEDED:
         did_work = false;
         break;
+      case MOJO_RESULT_INVALID_ARGUMENT:
+      case MOJO_RESULT_CANCELLED:
+      case MOJO_RESULT_BUSY:
+        // These results indicate a bug in "our" code (e.g., race conditions).
+        // Fall through.
       default:
         base::debug::Alias(&result);
         // Unexpected result is likely fatal, crash so we can determine cause.
         CHECK(false);
     }
   }
   // To keep memory usage under control, delete the WaitState object at the end
   // if it's vectors are too big by a factor of 2. Pre-C++11 doesn't have a way
   // to shrink vectors, so just get rid of them and re-create on the next round.
   if (run_state_->wait_state->handles.capacity() >
@@ skipping 99 matching lines @@
 void MessagePumpMojo::WillSignalHandler() {
   FOR_EACH_OBSERVER(Observer, observers_, WillSignalHandler());
 }
 
 void MessagePumpMojo::DidSignalHandler() {
   FOR_EACH_OBSERVER(Observer, observers_, DidSignalHandler());
 }
 
 }  // namespace common
 }  // namespace mojo