fix a bug in scrolling BitmapText gpu cached textblobs

src/gpu/GrTextBlobCache.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrTextBlobCache.h"
 
 static const int kVerticesPerGlyph = 4;
@@ skipping 18 matching lines @@
     cacheBlob->fVertices = sizeof(BitmapTextBlob) + reinterpret_cast<unsigned char*>(cacheBlob);
     cacheBlob->fGlyphs = reinterpret_cast<GrGlyph**>(cacheBlob->fVertices + verticesCount);
     cacheBlob->fRuns = reinterpret_cast<BitmapTextBlob::Run*>(cacheBlob->fGlyphs + glyphCount);
 
     // Initialize runs
     for (int i = 0; i < runCount; i++) {
         SkNEW_PLACEMENT(&cacheBlob->fRuns[i], BitmapTextBlob::Run);
     }
     cacheBlob->fRunCount = runCount;
     cacheBlob->fPool = &fPool;
-
-#ifdef SK_DEBUG
-    cacheBlob->fTotalXError = 0;
-    cacheBlob->fTotalYError = 0;
-#endif
     return cacheBlob;
 }
 
 void GrTextBlobCache::freeAll() {
     SkTDynamicHash<BitmapTextBlob, BitmapTextBlob::Key>::Iter iter(&fCache);
     while (!iter.done()) {
         (&(*iter))->unref();
         ++iter;
     }
     fCache.rewind();
 }