Make Dispatcher::Type an enum class.

mojo/edk/system/dispatcher.h

Index: mojo/edk/system/dispatcher.h
diff --git a/mojo/edk/system/dispatcher.h b/mojo/edk/system/dispatcher.h
index 8d7e1cb665c3034a5cac585b0bc958f8224d7d98..d7b7780ccf198ffe102331c241b77d372ba58b68 100644
--- a/mojo/edk/system/dispatcher.h
+++ b/mojo/edk/system/dispatcher.h
@@ -8,6 +8,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include <ostream>
 #include <vector>
 
 #include "base/macros.h"
@@ -59,15 +60,15 @@ DispatcherTryStartTransport(Dispatcher* dispatcher);
 class MOJO_SYSTEM_IMPL_EXPORT Dispatcher
     : public base::RefCountedThreadSafe<Dispatcher> {
  public:
-  enum Type {
-    kTypeUnknown = 0,
-    kTypeMessagePipe,
-    kTypeDataPipeProducer,
-    kTypeDataPipeConsumer,
-    kTypeSharedBuffer,
+  enum class Type {
+    UNKNOWN = 0,
+    MESSAGE_PIPE,
+    DATA_PIPE_PRODUCER,
+    DATA_PIPE_CONSUMER,
+    SHARED_BUFFER,
 
     // "Private" types (not exposed via the public interface):
-    kTypePlatformHandle = -1
+    PLATFORM_HANDLE = -1
   };
   virtual Type GetType() const = 0;
 
@@ -399,6 +400,12 @@ class MOJO_SYSTEM_IMPL_EXPORT DispatcherTransport {
   // Copy and assign allowed.
 };
 
+// So logging macros and |DCHECK_EQ()|, etc. work.
+MOJO_SYSTEM_IMPL_EXPORT inline std::ostream& operator<<(std::ostream& out,
+                                                        Dispatcher::Type type) {
+  return out << static_cast<int>(type);
+}
+
 }  // namespace system
 }  // namespace mojo