Remove some unnecessary uses of SkOnce.

src/core/SkScaledImageCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkScaledImageCache.h"
 #include "SkMipMap.h"
-#include "SkOnce.h"
 #include "SkPixelRef.h"
 #include "SkRect.h"
 
 // This can be defined by the caller's build system
 //#define SK_USE_DISCARDABLE_SCALEDIMAGECACHE
 
 #ifndef SK_DISCARDABLEMEMORY_SCALEDIMAGECACHE_COUNT_LIMIT
 #   define SK_DISCARDABLEMEMORY_SCALEDIMAGECACHE_COUNT_LIMIT   1024
 #endif
 
@@ skipping 645 matching lines @@
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "SkThread.h"
 
 SK_DECLARE_STATIC_MUTEX(gMutex);
 static SkScaledImageCache* gScaledImageCache = NULL;
 static void cleanup_gScaledImageCache() { SkDELETE(gScaledImageCache); }
 
-static void create_cache(int) {
+/** Must hold gMutex when calling. */
+static SkScaledImageCache* get_cache() {
+    // gMutex is always held when this is called, so we don't need to be fancy in here.
+    if (NULL == gScaledImageCache) {
 #ifdef SK_USE_DISCARDABLE_SCALEDIMAGECACHE
-    gScaledImageCache = SkNEW_ARGS(SkScaledImageCache, (SkDiscardableMemory::Create));
+        gScaledImageCache = SkNEW_ARGS(SkScaledImageCache, (SkDiscardableMemory::Create));
 #else
-    gScaledImageCache = SkNEW_ARGS(SkScaledImageCache, (SK_DEFAULT_IMAGE_CACHE_LIMIT));
+        gScaledImageCache = SkNEW_ARGS(SkScaledImageCache, (SK_DEFAULT_IMAGE_CACHE_LIMIT));
 #endif
-}
-
-static SkScaledImageCache* get_cache() {
-    SK_DECLARE_STATIC_ONCE(once);
-    SkOnce(&once, create_cache, 0, cleanup_gScaledImageCache);
-    SkASSERT(NULL != gScaledImageCache);
+        atexit(cleanup_gScaledImageCache);
+    }
     return gScaledImageCache;
 }
 
 
 SkScaledImageCache::ID* SkScaledImageCache::FindAndLock(
                                 uint32_t pixelGenerationID,
                                 int32_t width,
                                 int32_t height,
                                 SkBitmap* scaled) {
     SkAutoMutexAcquire am(gMutex);
@@ skipping 78 matching lines @@
     return SkScaledImageCache::GetBytesUsed();
 }
 
 size_t SkGraphics::GetImageCacheByteLimit() {
     return SkScaledImageCache::GetByteLimit();
 }
 
 size_t SkGraphics::SetImageCacheByteLimit(size_t newLimit) {
     return SkScaledImageCache::SetByteLimit(newLimit);
 }