Revert of SK_DECLARE_STATIC_MUTEX -> static SkMutex

include/private/SkMutex.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkMutex_DEFINED
 #define SkMutex_DEFINED
 
 #include "../private/SkSemaphore.h"
 #include "../private/SkThreadID.h"
 #include "SkTypes.h"
 
+// TODO: no need for this anymore.
+#define SK_DECLARE_STATIC_MUTEX(name) static SkMutex name;
+
 class SkMutex {
 public:
     constexpr SkMutex() = default;
 
     SkMutex(const SkMutex&)            = delete;
     SkMutex& operator=(const SkMutex&) = delete;
 
     void acquire() {
         fSemaphore.wait();
         SkDEBUGCODE(fOwner = SkGetThreadID();)
@@ skipping 64 matching lines @@
     Lock &fLock;
 };
 
 typedef SkAutoTAcquire<SkMutex> SkAutoMutexAcquire;
 #define SkAutoMutexAcquire(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexAcquire)
 
 typedef SkAutoTExclusive<SkMutex> SkAutoMutexExclusive;
 #define SkAutoMutexExclusive(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexExclusive)
 
 #endif//SkMutex_DEFINED