change old picture serialization to really handle images

src/core/SkWriteBuffer.cpp

Index: src/core/SkWriteBuffer.cpp
diff --git a/src/core/SkWriteBuffer.cpp b/src/core/SkWriteBuffer.cpp
index d2eb8c5d8d234c7aaaf7b491b7e8a78d93c8628e..82e031e461b4f1b4e6b81d6229d1ba6d661e5fa7 100644
--- a/src/core/SkWriteBuffer.cpp
+++ b/src/core/SkWriteBuffer.cpp
@@ -218,6 +218,35 @@ void SkWriteBuffer::writeBitmap(const SkBitmap& bitmap) {
     SkBitmap::WriteRawPixels(this, bitmap);
 }
 
+static bool try_write_encoded(SkWriteBuffer* buffer, SkData* encoded, SkIPoint origin) {
+    SkPixelSerializer* ps = buffer->getPixelSerializer();
+    // Assumes that if the client did not set a serializer, they are
+    // happy to get the encoded data.
+    if (!ps || ps->useEncodedData(encoded->data(), encoded->size())) {
+        write_encoded_bitmap(buffer, encoded, origin);
+        return true;
+    }
+    return false;
+}
+
+void SkWriteBuffer::writeImage(const SkImage* image) {
+    this->writeInt(image->width());
+    this->writeInt(image->height());
+
+    SkIPoint origin;
+    SkAutoTUnref<SkData> encoded(image->refEncodedData(&origin));
+    if (encoded && try_write_encoded(this, encoded, origin)) {
+        return;
+    }
+
+    encoded.reset(image->encode(SkImageEncoder::kPNG_Type, 100));
+    if (encoded && try_write_encoded(this, encoded, SkIPoint::Make(0, 0))) {
+        return;
+    }
+    
+    this->writeUInt(0); // signal no pixels
+}
+
 void SkWriteBuffer::writeTypeface(SkTypeface* obj) {
     if (NULL == obj || NULL == fTFSet) {
         fWriter.write32(0);