mojo: Remove Pass() from MOJO_MOVE_ONLY_TYPE

mojo/public/cpp/system/macros.h

Index: mojo/public/cpp/system/macros.h
diff --git a/mojo/public/cpp/system/macros.h b/mojo/public/cpp/system/macros.h
index 212701287278e072d819c18374252598c6bd972a..d477891be4accae90f647c4666989a23f24fbfc6 100644
--- a/mojo/public/cpp/system/macros.h
+++ b/mojo/public/cpp/system/macros.h
@@ -32,16 +32,16 @@ char(&ArraySizeHelper(const T(&array)[N]))[N];
 }  // namespace mojo
 #define MOJO_ARRAYSIZE(array) (sizeof(::mojo::internal::ArraySizeHelper(array)))
 
-// Used to make a type move-only. See Chromium's base/move.h for more
+// Used to make a type non-copyable. See Chromium's base/move.h for more
 // details. The MoveOnlyTypeForCPP03 typedef is for Chromium's base/callback.h
-// to tell that this type is move-only.
+// to tell that this type is move-only, allowing these types to be bound or
+// passed to Callbacks.
 #define MOJO_MOVE_ONLY_TYPE(type)                                              \
  private:                                                                      \
   type(const type&) = delete;                                                  \
   void operator=(const type&) = delete;                                        \
                                                                                \
  public:                                                                       \
-  type&& Pass() MOJO_WARN_UNUSED_RESULT { return static_cast<type&&>(*this); } \
   typedef void MoveOnlyTypeForCPP03;                                           \
                                                                                \
  private: