Convert core.{h,cc} to use mojo::system::Mutex (and MutexLocker).

mojo/edk/system/core.h

 // Copyright 2013 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.
 
 #ifndef MOJO_EDK_SYSTEM_CORE_H_
 #define MOJO_EDK_SYSTEM_CORE_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/synchronization/lock.h"
 #include "mojo/edk/system/handle_table.h"
 #include "mojo/edk/system/mapping_table.h"
 #include "mojo/edk/system/memory.h"
+#include "mojo/edk/system/mutex.h"
 #include "mojo/edk/system/system_impl_export.h"
 #include "mojo/public/c/system/buffer.h"
 #include "mojo/public/c/system/data_pipe.h"
 #include "mojo/public/c/system/message_pipe.h"
 #include "mojo/public/c/system/types.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
 
 namespace embedder {
@@ skipping 141 matching lines @@
   // preinitialized to |static_cast<uint32_t>(-1)|.
   MojoResult WaitManyInternal(const MojoHandle* handles,
                               const MojoHandleSignals* signals,
                               uint32_t num_handles,
                               MojoDeadline deadline,
                               uint32_t* result_index,
                               HandleSignalsState* signals_states);
 
   embedder::PlatformSupport* const platform_support_;
 
-  // TODO(vtl): |handle_table_lock_| should be a reader-writer lock (if only we
+  // TODO(vtl): |handle_table_mutex_| should be a reader-writer lock (if only we
   // had them).
-  base::Lock handle_table_lock_;  // Protects |handle_table_|.
-  HandleTable handle_table_;
+  Mutex handle_table_mutex_;
+  HandleTable handle_table_ MOJO_GUARDED_BY(handle_table_mutex_);
 
-  base::Lock mapping_table_lock_;  // Protects |mapping_table_|.
-  MappingTable mapping_table_;
+  Mutex mapping_table_mutex_;
+  MappingTable mapping_table_ MOJO_GUARDED_BY(mapping_table_mutex_);
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(Core);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_CORE_H_