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

mojo/edk/util/mutex.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A mutex class, with support for thread annotations.
 //
 // TODO(vtl): Add support for non-exclusive (reader) locks.
 
-#ifndef MOJO_EDK_SYSTEM_MUTEX_H_
-#define MOJO_EDK_SYSTEM_MUTEX_H_
+#ifndef MOJO_EDK_UTIL_MUTEX_H_
+#define MOJO_EDK_UTIL_MUTEX_H_
 
 #include <pthread.h>
 
-#include "mojo/edk/system/thread_annotations.h"
+#include "mojo/edk/util/thread_annotations.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
-namespace system {
-
-// So |Mutex| can friend it.
-class CondVar;
+namespace util {
 
 // Mutex -----------------------------------------------------------------------
 
+class CondVar;
+
 class MOJO_LOCKABLE Mutex {
  public:
 #if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
   Mutex() { pthread_mutex_init(&impl_, nullptr); }
   ~Mutex() { pthread_mutex_destroy(&impl_); }
 
   // Takes an exclusive lock.
   void Lock() MOJO_EXCLUSIVE_LOCK_FUNCTION() { pthread_mutex_lock(&impl_); }
 
   // Releases a lock.
@@ skipping 36 matching lines @@
     this->mutex_->Lock();
   }
   ~MutexLocker() MOJO_UNLOCK_FUNCTION() { this->mutex_->Unlock(); }
 
  private:
   Mutex* const mutex_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(MutexLocker);
 };
 
-}  // namespace system
+}  // namespace util
 }  // namespace mojo
 
-#endif  // MOJO_EDK_SYSTEM_MUTEX_H_
+#endif  // MOJO_EDK_UTIL_MUTEX_H_