Add the lazy decoder from PictureFlags to SkImageDecoder

src/images/SkImageDecoder.cpp

Index: src/images/SkImageDecoder.cpp
diff --git a/src/images/SkImageDecoder.cpp b/src/images/SkImageDecoder.cpp
index 5d94bb1c2db97efd618320213210ef91ee363329..9b8ae726acb26938d605244b0ccf34e8debe2fa7 100644
--- a/src/images/SkImageDecoder.cpp
+++ b/src/images/SkImageDecoder.cpp
@@ -8,12 +8,16 @@
 
 #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)
@@ -280,6 +284,22 @@ bool SkImageDecoder::DecodeFile(const char file[], SkBitmap* bm,
     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) {