Use sk_sp text blob APIs

src/core/SkTextBlob.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTextBlobRunIterator.h"
 
 #include "SkReadBuffer.h"
@@ skipping 468 matching lines @@
     , fRunCount(0)
     , fDeferredBounds(false)
     , fLastRun(0) {
     fBounds.setEmpty();
 }
 
 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();
     }
 }
 
 SkRect SkTextBlobBuilder::TightRunBounds(const SkTextBlob::RunRecord& run) {
     SkRect bounds;
     SkPaint paint;
     run.font().applyToPaint(&paint);
 
     if (SkTextBlob::kDefault_Positioning == run.positioning()) {
         paint.measureText(run.glyphBuffer(), run.glyphCount() * sizeof(uint16_t), &bounds);
@@ skipping 270 matching lines @@
     )
 
     fStorageUsed = 0;
     fStorageSize = 0;
     fRunCount = 0;
     fLastRun = 0;
     fBounds.setEmpty();
 
     return sk_sp<SkTextBlob>(blob);
 }