SkValidatingReadBuffer: make sure we don't call readTypeface().

src/core/SkValidatingReadBuffer.cpp

Index: src/core/SkValidatingReadBuffer.cpp
diff --git a/src/core/SkValidatingReadBuffer.cpp b/src/core/SkValidatingReadBuffer.cpp
index e00613b8b5684699fc0630270f2eef32ade38bc4..bc5611a3e382902878ca99256f6d26ff0e80c3c2 100644
--- a/src/core/SkValidatingReadBuffer.cpp
+++ b/src/core/SkValidatingReadBuffer.cpp
@@ -213,6 +213,7 @@ uint32_t SkValidatingReadBuffer::getArrayCount() {
 }
 
 SkTypeface* SkValidatingReadBuffer::readTypeface() {
+    SkASSERT(false);
     // TODO: Implement this (securely) when needed
     return nullptr;
 }