Handle zero-length encoded images gracefully during deserialization

src/core/SkWriteBuffer.cpp

Index: src/core/SkWriteBuffer.cpp
diff --git a/src/core/SkWriteBuffer.cpp b/src/core/SkWriteBuffer.cpp
index ac3d678dbc011a70b9c38cdd91ce4199f633750c..1dfe0b3972c62b6b8e68cc6f6d92dc8782935b97 100644
--- a/src/core/SkWriteBuffer.cpp
+++ b/src/core/SkWriteBuffer.cpp
@@ -223,7 +223,7 @@ void SkWriteBuffer::writeImage(const SkImage* image) {
     this->writeInt(image->height());
 
     SkAutoTUnref<SkData> encoded(image->encode(this->getPixelSerializer()));
-    if (encoded) {
+    if (encoded && encoded->size() > 0) {
         write_encoded_bitmap(this, encoded, SkIPoint::Make(0, 0));
         return;
     }