change pixel-serializer to support reencoding existing data

src/image/SkImage.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBitmapCache.h"
 #include "SkCanvas.h"
@@ skipping 56 matching lines @@
     }
 }
 
 SkShader* SkImage::newShader(SkShader::TileMode tileX,
                              SkShader::TileMode tileY,
                              const SkMatrix* localMatrix) const {
     return SkImageShader::Create(this, tileX, tileY, localMatrix);
 }
 
 SkData* SkImage::encode(SkImageEncoder::Type type, int quality) const {
+    SkAutoDataUnref encoded(this->refEncoded());
+    if (encoded) {
+        SkAutoDataUnref reencoded(SkImageEncoder::ReencodeData(encoded, type));
+        if (reencoded) {
+            return reencoded.detach();
+        }
+    }
+
     SkBitmap bm;
     if (as_IB(this)->getROPixels(&bm)) {
         return SkImageEncoder::EncodeData(bm, type, quality);
     }
     return nullptr;
 }
 
 namespace {
 
 class DefaultSerializer :  public SkPixelSerializer {
 protected:
-    bool onUseEncodedData(const void *data, size_t len) override {
-        return true;
-    }
-
     SkData* onEncodePixels(const SkImageInfo& info, const void* pixels, size_t rowBytes) override {
         return SkImageEncoder::EncodeData(info, pixels, rowBytes, SkImageEncoder::kPNG_Type, 100);
     }
 };
 
 } // anonymous namespace
 
 SkData* SkImage::encode(SkPixelSerializer* serializer) const {
     DefaultSerializer defaultSerializer;
     SkPixelSerializer* effectiveSerializer = serializer ? serializer : &defaultSerializer;
 
     SkAutoTUnref<SkData> encoded(this->refEncoded());
-    if (encoded && effectiveSerializer->useEncodedData(encoded->data(), encoded->size())) {
-        return encoded.detach();
+    if (encoded) {
+        encoded.reset(effectiveSerializer->reencodeData(encoded));
+        if (encoded) {
+            return encoded.detach();
+        }
     }
 
     SkBitmap bm;
     SkAutoPixmapUnlock apu;
     if (as_IB(this)->getROPixels(&bm) && bm.requestLock(&apu)) {
-        const SkPixmap& pmap = apu.pixmap();
-        return effectiveSerializer->encodePixels(pmap.info(), pmap.addr(), pmap.rowBytes());
+        return effectiveSerializer->encodePixels(apu.pixmap());
     }
 
     return nullptr;
 }
 
 SkData* SkImage::refEncoded() const {
     return as_IB(this)->onRefEncoded();
 }
 
 SkImage* SkImage::NewFromEncoded(SkData* encoded, const SkIRect* subset) {
@@ skipping 202 matching lines @@
 
 SkImage* SkImage::NewFromAdoptedTexture(GrContext*, const GrBackendTextureDesc&, SkAlphaType) {
     return nullptr;
 }
 
 SkImage* SkImage::NewFromTextureCopy(GrContext*, const GrBackendTextureDesc&, SkAlphaType) {
     return nullptr;
 }
 
 #endif