Use sk_sp text blob APIs

src/core/SkTextBlob.cpp

Index: src/core/SkTextBlob.cpp
diff --git a/src/core/SkTextBlob.cpp b/src/core/SkTextBlob.cpp
index 35adc24a34ff6610aa335d542c04c89f040c3291..ca75a2e0381d108e884bac0325518ecc40e85782 100644
--- a/src/core/SkTextBlob.cpp
+++ b/src/core/SkTextBlob.cpp
@@ -486,7 +486,7 @@ SkTextBlobBuilder::~SkTextBlobBuilder() {
     if (nullptr != fStorage.get()) {
         // We are abandoning runs and must destruct the associated font data.
         // The easiest way to accomplish that is to use the blob destructor.
-        build()->unref();
+        this->make();
     }
 }