Revert of Update mojo sdk to rev c02a28868825edfa57ab77947b8cb15e741c5598

third_party/mojo/src/mojo/edk/system/channel_manager.h

Index: third_party/mojo/src/mojo/edk/system/channel_manager.h
diff --git a/third_party/mojo/src/mojo/edk/system/channel_manager.h b/third_party/mojo/src/mojo/edk/system/channel_manager.h
index 014c1b3a7836597cea55e8e22d4abb024d68dc43..9a9c0e8501f3b5dde0cc5b6eb67e76db74abced5 100644
--- a/third_party/mojo/src/mojo/edk/system/channel_manager.h
+++ b/third_party/mojo/src/mojo/edk/system/channel_manager.h
@@ -10,9 +10,9 @@
 #include "base/callback_forward.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/edk/system/channel_id.h"
-#include "mojo/edk/system/mutex.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace base {
@@ -135,15 +135,12 @@
   const scoped_refptr<base::TaskRunner> io_thread_task_runner_;
   ConnectionManager* const connection_manager_;
 
-  // Note: |Channel| methods should not be called under |mutex_|.
-  // TODO(vtl): Annotate the above rule using |MOJO_ACQUIRED_{BEFORE,AFTER}()|,
-  // once clang actually checks such annotations.
-  // https://github.com/domokit/mojo/issues/313
-  mutable Mutex mutex_;
+  // Note: |Channel| methods should not be called under |lock_|.
+  mutable base::Lock lock_;  // Protects the members below.
 
   using ChannelIdToChannelMap =
       base::hash_map<ChannelId, scoped_refptr<Channel>>;
-  ChannelIdToChannelMap channels_ MOJO_GUARDED_BY(mutex_);
+  ChannelIdToChannelMap channels_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(ChannelManager);
 };