EDK: Move mutex.*, cond_var.*, and thread_annotations.h to //mojo/edk/util.

mojo/edk/system/master_connection_manager.h

Index: mojo/edk/system/master_connection_manager.h
diff --git a/mojo/edk/system/master_connection_manager.h b/mojo/edk/system/master_connection_manager.h
index 81ce662d7676fa409de9aa263592ef65096dd1fb..e751e4decf9851573eed2eb261c2b7ba8f2f1ae6 100644
--- a/mojo/edk/system/master_connection_manager.h
+++ b/mojo/edk/system/master_connection_manager.h
@@ -13,7 +13,8 @@
 #include "mojo/edk/embedder/platform_task_runner.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/edk/system/connection_manager.h"
-#include "mojo/edk/system/mutex.h"
+#include "mojo/edk/util/mutex.h"
+#include "mojo/edk/util/thread_annotations.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace base {
@@ -147,7 +148,7 @@ class MasterConnectionManager final : public ConnectionManager {
 
   // Note: |mutex_| is not needed in the constructor, |Init()|,
   // |Shutdown()|/|ShutdownOnPrivateThread()|, or the destructor
-  Mutex mutex_;
+  util::Mutex mutex_;
 
   ProcessIdentifier next_process_identifier_ MOJO_GUARDED_BY(mutex_);