Add the lazy decoder from PictureFlags to SkImageDecoder

src/images/SkImageDecoder.cpp

 /*
  * 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.
  */
 
 
 #include "SkImageDecoder.h"
 #include "SkBitmap.h"
+#include "SkData.h"
+#include "SkForceLinking.h"
 #include "SkImagePriv.h"
 #include "SkPixelRef.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkCanvas.h"
 
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
 SK_DEFINE_INST_COUNT(SkImageDecoder::Peeker)
 SK_DEFINE_INST_COUNT(SkImageDecoder::Chooser)
 SK_DEFINE_INST_COUNT(SkImageDecoderFactory)
 
 static SkBitmap::Config gDeviceConfig = SkBitmap::kNo_Config;
 
 SkBitmap::Config SkImageDecoder::GetDeviceConfig()
 {
     return gDeviceConfig;
 }
@@ skipping 246 matching lines @@
     SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(file));
     if (stream.get()) {
         if (SkImageDecoder::DecodeStream(stream, bm, pref, mode, format)) {
             bm->pixelRef()->setURI(file);
             return true;
         }
     }
     return false;
 }
 
+SkLruImageCache SkImageDecoder::fLruImageCache(1024*1024);
+SkBitmapFactory SkImageDecoder::fLazyBitmapFactory(&SkImageDecoder::DecodeMemoryToTarget);
+
+bool SkImageDecoder::LazyDecodeBitmap(const void* buffer, size_t size, SkBitmap* bitmap) {
+    void* copiedBuffer = sk_malloc_throw(size);
+    memcpy(copiedBuffer, buffer, size);
+    SkAutoDataUnref data(SkData::NewFromMalloc(copiedBuffer, size));
+
+    static bool gOnce;
+    if (!gOnce) {
+        fLazyBitmapFactory.setImageCache(&fLruImageCache);
+        gOnce = true;
+    }
+    return fLazyBitmapFactory.installPixelRef(data, bitmap);
+}
+
 bool SkImageDecoder::DecodeMemory(const void* buffer, size_t size, SkBitmap* bm,
                           SkBitmap::Config pref, Mode mode, Format* format) {
     if (0 == size) {
         return false;
     }
     SkASSERT(buffer);
 
     SkMemoryStream  stream(buffer, size);
     return SkImageDecoder::DecodeStream(&stream, bm, pref, mode, format);
 }
@@ skipping 161 matching lines @@
             if (kUnknown_Format == *format) {
                 if (stream->rewind()) {
                     *format = GetStreamFormat(stream);
                 }
             }
         }
         delete codec;
     }
     return success;
 }