use dynamic hash to speed up scaledimagecache

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 "SkPixelRef.h"
@@ skipping 131 matching lines @@
     return rec.fKey == key;
 }
 }
 
 class SkScaledImageCache::Hash : public SkTDynamicHash<SkScaledImageCache::Rec,
                                    Key, key_from_rec, hash_from_key,
                                    eq_rec_key> {};
 
 ///////////////////////////////////////////////////////////////////////////////
 
-//#define USE_HASH
+#define USE_HASH
 
 SkScaledImageCache::SkScaledImageCache(size_t byteLimit) {
     fHead = NULL;
     fTail = NULL;
 #ifdef USE_HASH
     fHash = new Hash;
 #else
     fHash = NULL;
 #endif
     fBytesUsed = 0;
@@ skipping 355 matching lines @@
     return SkScaledImageCache::GetBytesUsed();
 }
 
 size_t SkGraphics::GetImageCacheByteLimit() {
     return SkScaledImageCache::GetByteLimit();
 }
 
 size_t SkGraphics::SetImageCacheByteLimit(size_t newLimit) {
     return SkScaledImageCache::SetByteLimit(newLimit);
 }