SkOnce in is_lcd_supported instead of hand rolled double-checked locking.

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 33 matching lines @@
  */
 static void sk_membar_acquire__after_atomic_dec();
 
 /** If sk_atomic_conditional_inc does not act as an acquire (L/SL) barrier,
  *  this must act as an acquire (L/SL) memory barrier and as a compiler barrier.
  */
 static void sk_membar_acquire__after_atomic_conditional_inc();
 
 #include SK_ATOMICS_PLATFORM_H
 
-// This is POD and must be zero-initialized.
-struct SkSpinlock {
-    void acquire() {
-        SkASSERT(shouldBeZero == 0);
-        // No memory barrier needed, but sk_atomic_cas gives us at least release anyway.
-        while (!sk_atomic_cas(&thisIsPrivate, 0, 1)) {
-            // spin
-        }
-    }
-
-    void release() {
-        SkASSERT(shouldBeZero == 0);
-        // This requires a release memory barrier before storing, which sk_atomic_cas guarantees.
-        SkAssertResult(sk_atomic_cas(&thisIsPrivate, 1, 0));
-    }
-
-    int32_t thisIsPrivate;
-    SkDEBUGCODE(int32_t shouldBeZero;)
-};
-
-class SkAutoSpinlock : SkNoncopyable {
-public:
-    explicit SkAutoSpinlock(SkSpinlock* lock) : fLock(lock) { fLock->acquire(); }
-    ~SkAutoSpinlock() { fLock->release(); }
-private:
-    SkSpinlock* fLock;
-};
-#define SkAutoSpinlock(...) SK_REQUIRE_LOCAL_VAR(SkAutoSpinlock)
-
 /** SK_MUTEX_PLATFORM_H must provide the following (or equivalent) declarations.
 
 class SkBaseMutex {
 public:
     void acquire();
     void release();
 };
 
 class SkMutex : SkBaseMutex {
 public:
@@ skipping 35 matching lines @@
             fMutex = NULL;
         }
     }
 
 private:
     SkBaseMutex* fMutex;
 };
 #define SkAutoMutexAcquire(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexAcquire)
 
 #endif