Adding error checks to SkRBuffer

src/core/SkFlattenableBuffers.cpp

Index: src/core/SkFlattenableBuffers.cpp
diff --git a/src/core/SkFlattenableBuffers.cpp b/src/core/SkFlattenableBuffers.cpp
index 54d18d1c2f03eabcb137cfd289230f97b8c1ca17..9da4dd9ee48641769dc592ab4255f37d07bc49ca 100644
--- a/src/core/SkFlattenableBuffers.cpp
+++ b/src/core/SkFlattenableBuffers.cpp
@@ -89,6 +89,10 @@ SkXfermode* SkFlattenableReadBuffer::readXfermode() {
     return this->readFlattenableT<SkXfermode>();
 }
 
+bool SkFlattenableReadBuffer::validate(bool isValid) {
+    return true;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 SkFlattenableWriteBuffer::SkFlattenableWriteBuffer() {