Makes HandleWatcher block until no longer waiting on pipe

mojo/common/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/common/message_pump_mojo.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/alias.h"
@@ skipping 139 matching lines @@
                    MOJO_READ_MESSAGE_FLAG_MAY_DISCARD);
   } else if (result > 0) {
     const size_t index = static_cast<size_t>(result);
     DCHECK(handlers_.find(wait_state.handles[index]) != handlers_.end());
     handlers_[wait_state.handles[index]].handler->OnHandleReady(
         wait_state.handles[index]);
   } else {
     switch (result) {
       case MOJO_RESULT_CANCELLED:
       case MOJO_RESULT_FAILED_PRECONDITION:
-      case MOJO_RESULT_INVALID_ARGUMENT:
         RemoveFirstInvalidHandle(wait_state);
         break;
       case MOJO_RESULT_DEADLINE_EXCEEDED:
         break;
       default:
         base::debug::Alias(&result);
         // Unexpected result is likely fatal, crash so we can determine cause.
         CHECK(false);
     }
   }
@@ skipping 12 matching lines @@
       i->second.handler->OnHandleError(i->first, MOJO_RESULT_DEADLINE_EXCEEDED);
     }
   }
 }
 
 void MessagePumpMojo::RemoveFirstInvalidHandle(const WaitState& wait_state) {
   // TODO(sky): deal with control pipe going bad.
   for (size_t i = 1; i < wait_state.handles.size(); ++i) {
     const MojoResult result =
         Wait(wait_state.handles[i], wait_state.wait_signals[i], 0);
-    if (result == MOJO_RESULT_INVALID_ARGUMENT ||
-        result == MOJO_RESULT_FAILED_PRECONDITION ||
-        result == MOJO_RESULT_CANCELLED) {
+    if (result == MOJO_RESULT_INVALID_ARGUMENT) {
+      // We should never have an invalid argument. If we do it indicates
+      // RemoveHandler() was not invoked and is likely to cause problems else
+      // where in the stack if we ignore it.
+      CHECK(false);
+    } else if (result == MOJO_RESULT_FAILED_PRECONDITION ||
+               result == MOJO_RESULT_CANCELLED) {
       // Remove the handle first, this way if OnHandleError() tries to remove
       // the handle our iterator isn't invalidated.
       DCHECK(handlers_.find(wait_state.handles[i]) != handlers_.end());
       MessagePumpMojoHandler* handler =
           handlers_[wait_state.handles[i]].handler;
       handlers_.erase(wait_state.handles[i]);
       handler->OnHandleError(wait_state.handles[i], result);
       return;
     }
   }
@@ skipping 28 matching lines @@
       min_time = i->second.deadline;
   }
   return min_time.is_null() ? MOJO_DEADLINE_INDEFINITE :
       std::max(static_cast<MojoDeadline>(0),
                static_cast<MojoDeadline>(
                    (min_time - internal::NowTicks()).InMicroseconds()));
 }
 
 }  // namespace common
 }  // namespace mojo