Make Dispatcher::Type an enum class.

mojo/edk/system/simple_dispatcher_unittest.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.
 
 // NOTE(vtl): Some of these tests are inherently flaky (e.g., if run on a
 // heavily-loaded system). Sorry. |test::EpsilonTimeout()| may be increased to
 // increase tolerance and reduce observed flakiness (though doing so reduces the
 // meaningfulness of the test).
 
 #include "mojo/edk/system/simple_dispatcher.h"
@@ skipping 42 matching lines @@
     CHECK_EQ(new_satisfiable_signals & state_.satisfied_signals,
              state_.satisfied_signals);
 
     if (new_satisfiable_signals == state_.satisfiable_signals)
       return;
 
     state_.satisfiable_signals = new_satisfiable_signals;
     HandleSignalsStateChangedNoLock();
   }
 
-  Type GetType() const override { return kTypeUnknown; }
+  Type GetType() const override { return Type::UNKNOWN; }
 
  private:
   friend class base::RefCountedThreadSafe<MockSimpleDispatcher>;
   ~MockSimpleDispatcher() override {}
 
   scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
       override {
     scoped_refptr<MockSimpleDispatcher> rv(new MockSimpleDispatcher());
     rv->state_ = state_;
     return scoped_refptr<Dispatcher>(rv.get());
@@ skipping 526 matching lines @@
     // Since we closed before joining, we can't say much about what each thread
     // saw as the state.
   }
 }
 
 // TODO(vtl): Stress test?
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo