Last set of fixes to make the src/mojo/edk pass the page cycler.

mojo/edk/system/dispatcher.cc

Index: mojo/edk/system/dispatcher.cc
diff --git a/mojo/edk/system/dispatcher.cc b/mojo/edk/system/dispatcher.cc
index e7426e513f284b9becdb38f31f72d4cb8bd0c331..e5f078793610b383816210371029c2a36b0ff1aa 100644
--- a/mojo/edk/system/dispatcher.cc
+++ b/mojo/edk/system/dispatcher.cc
@@ -453,6 +453,7 @@ void Dispatcher::StartSerialize(size_t* max_size,
   DCHECK(max_size);
   DCHECK(max_platform_handles);
   DCHECK(!is_closed_);
+  base::AutoLock locker(lock_);
   StartSerializeImplNoLock(max_size, max_platform_handles);
 }
 
@@ -467,13 +468,7 @@ bool Dispatcher::EndSerializeAndClose(void* destination,
   // shouldn't be in |Core|'s handle table.
   is_closed_ = true;
 
-#if !defined(NDEBUG)
-  // See the comment above |EndSerializeAndCloseImplNoLock()|. In brief: Locking
-  // isn't actually needed, but we need to satisfy assertions (which we don't
-  // want to remove or weaken).
   base::AutoLock locker(lock_);
-#endif
-
   return EndSerializeAndCloseImplNoLock(destination, actual_size,
                                         platform_handles);
 }