Fix thread unsafe mutex initialization.

include/core/SkThread.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkThread_DEFINED
 #define SkThread_DEFINED
 
@@ skipping 78 matching lines @@
     void assertHeld();  // If SK_DEBUG, assert this thread owns the mutex.
 };
 
 class SkMutex : SkBaseMutex {
 public:
     SkMutex();
     ~SkMutex();
 };
 
 #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name = ...
-#define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name = ...
 */
 
 #include SK_MUTEX_PLATFORM_H
 
 
 class SkAutoMutexAcquire : SkNoncopyable {
 public:
     explicit SkAutoMutexAcquire(SkBaseMutex& mutex) : fMutex(&mutex) {
         SkASSERT(fMutex != NULL);
         mutex.acquire();
@@ skipping 25 matching lines @@
         SkASSERT(fMutex);
         fMutex->assertHeld();
     }
 
 private:
     SkBaseMutex* fMutex;
 };
 #define SkAutoMutexAcquire(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexAcquire)
 
 #endif