Reland "EDK: Move //mojo/edk/system/waitable_event* to edk/util."

mojo/edk/util/waitable_event.h

Index: mojo/edk/util/waitable_event.h
diff --git a/mojo/edk/system/waitable_event.h b/mojo/edk/util/waitable_event.h
similarity index 96%
rename from mojo/edk/system/waitable_event.h
rename to mojo/edk/util/waitable_event.h
index 38c75e06564db3c1c1b44d236188be3b95c0172e..be64a66e720d6b4a6d8bcd2527e26068a9484954 100644
--- a/mojo/edk/system/waitable_event.h
+++ b/mojo/edk/util/waitable_event.h
@@ -7,8 +7,8 @@
 // analogous to Windows's Event. (Unlike these two, we have separate types for
 // the manual- and auto-reset versions.)
 
-#ifndef MOJO_EDK_SYSTEM_WAITABLE_EVENT_H_
-#define MOJO_EDK_SYSTEM_WAITABLE_EVENT_H_
+#ifndef MOJO_EDK_UTIL_WAITABLE_EVENT_H_
+#define MOJO_EDK_UTIL_WAITABLE_EVENT_H_
 
 #include "mojo/edk/util/cond_var.h"
 #include "mojo/edk/util/mutex.h"
@@ -16,7 +16,7 @@
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
-namespace system {
+namespace util {
 
 // AutoResetWaitableEvent ------------------------------------------------------
 
@@ -121,7 +121,7 @@ class ManualResetWaitableEvent {
   MOJO_DISALLOW_COPY_AND_ASSIGN(ManualResetWaitableEvent);
 };
 
-}  // namespace system
+}  // namespace util
 }  // namespace mojo
 
-#endif  // MOJO_EDK_SYSTEM_WAITABLE_EVENT_H_
+#endif  // MOJO_EDK_UTIL_WAITABLE_EVENT_H_