Revert of Modernize SkMutex and SkSemaphore.

src/lazy/SkDiscardableMemoryPool.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkDiscardableMemoryPool_DEFINED
 #define SkDiscardableMemoryPool_DEFINED
 
@@ skipping 34 matching lines @@
     virtual int getCacheHits() = 0;
     virtual int getCacheMisses() = 0;
     virtual void resetCacheHitsAndMisses() = 0;
     #endif
 
     /**
      *  This non-global pool can be used for unit tests to verify that
      *  the pool works.
      *  Without mutex, will be not be thread safe.
      */
-    static SkDiscardableMemoryPool* Create(size_t size, SkMutex* mutex = nullptr);
+    static SkDiscardableMemoryPool* Create(
+            size_t size, SkBaseMutex* mutex = nullptr);
 };
 
 /**
  *  Returns (and creates if needed) a threadsafe global
  *  SkDiscardableMemoryPool.
  */
 SkDiscardableMemoryPool* SkGetGlobalDiscardableMemoryPool();
 
 #if !defined(SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE)
 #define SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE (128 * 1024 * 1024)
 #endif
 
 #endif  // SkDiscardableMemoryPool_DEFINED