force readbuffer clients to use specialized readFoo for flattenables

src/core/SkFlattenableBuffers.cpp

Index: src/core/SkFlattenableBuffers.cpp
diff --git a/src/core/SkFlattenableBuffers.cpp b/src/core/SkFlattenableBuffers.cpp
index 50a47d5c47c209857f468fae86a575f0bd7c8de2..a8064f17bfdcdad164a403d6eddccdb8d1f573a0 100644
--- a/src/core/SkFlattenableBuffers.cpp
+++ b/src/core/SkFlattenableBuffers.cpp
@@ -34,6 +34,10 @@ void SkFlattenableReadBuffer::readPaint(SkPaint* paint) {
     paint->unflatten(*this);
 }
 
+SkFlattenable* SkFlattenableReadBuffer::readEffect(SkEffectType et) {
+    return this->readFlattenable();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 SkFlattenableWriteBuffer::SkFlattenableWriteBuffer() {
@@ -54,3 +58,4 @@ void SkFlattenableWriteBuffer::writePaint(const SkPaint& paint) {
 void SkFlattenableWriteBuffer::flattenObject(SkFlattenable* obj, SkFlattenableWriteBuffer& buffer) {
     obj->flatten(buffer);
 }
+