Improve Skia configuration.

skia/ext/SkThread_chrome.cc

-// Copyright (c) 2012 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.
-
-#include "third_party/skia/include/core/SkThread.h"
-
-#include <new>
-
-#include "base/atomicops.h"
-#include "base/basictypes.h"
-#include "base/logging.h"
-#include "base/synchronization/lock.h"
-
-/** Adds one to the int specified by the address (in a thread-safe manner), and
-    returns the previous value.
-    No additional memory barrier is required.
-    This must act as a compiler barrier.
-*/
-int32_t sk_atomic_inc(int32_t* addr) {
-  // sk_atomic_inc is expected to return the old value,
-  // Barrier_AtomicIncrement returns the new value.
-  return base::subtle::NoBarrier_AtomicIncrement(addr, 1) - 1;
-}
-
-/*  Subtracts one from the int specified by the address (in a thread-safe
-    manner), and returns the previous value.
-    Expected to act as a release (SL/S) memory barrier and a compiler barrier.
-*/
-int32_t sk_atomic_dec(int32_t* addr) {
-  // sk_atomic_dec is expected to return the old value,
-  // Barrier_AtomicIncrement returns the new value.
-  return base::subtle::Barrier_AtomicIncrement(addr, -1) + 1;
-}
-/** If sk_atomic_dec does not act as an aquire (L/SL) barrier, this is expected
-    to act as an aquire (L/SL) memory barrier and as a compiler barrier.
-*/
-void sk_membar_aquire__after_atomic_dec() { }
-
-/** Adds one to the int specified by the address iff the int specified by the
-    address is not zero (in a thread-safe manner), and returns the previous
-    value.
-    No additional memory barrier is required.
-    This must act as a compiler barrier.
-*/
-int32_t sk_atomic_conditional_inc(int32_t* addr) {
-    int32_t value = *addr;
-
-    while (true) {
-        if (value == 0) {
-            return 0;
-        }
-
-        int32_t before;
-        before = base::subtle::Acquire_CompareAndSwap(addr, value, value + 1);
-
-        if (before == value) {
-            return value;
-        } else {
-            value = before;
-        }
-    }
-}
-/** If sk_atomic_conditional_inc does not act as an aquire (L/SL) barrier, this
-    is expected to act as an aquire (L/SL) memory barrier and as a compiler
-    barrier.
-*/
-void sk_membar_aquire__after_atomic_conditional_inc() { }
-
-SkMutex::SkMutex() {
-  COMPILE_ASSERT(sizeof(base::Lock) <= sizeof(fStorage), Lock_is_too_big_for_SkMutex);
-  base::Lock* lock = reinterpret_cast<base::Lock*>(fStorage);
-  new(lock) base::Lock();
-}
-
-SkMutex::~SkMutex() {
-  base::Lock* lock = reinterpret_cast<base::Lock*>(fStorage);
-  lock->~Lock();
-}
-
-void SkMutex::acquire() {
-  base::Lock* lock = reinterpret_cast<base::Lock*>(fStorage);
-  lock->Acquire();
-}
-
-void SkMutex::release() {
-  base::Lock* lock = reinterpret_cast<base::Lock*>(fStorage);
-  lock->Release();
-}