fix a bug in scrolling BitmapText gpu cached textblobs

src/gpu/GrAtlasTextContext.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrAtlasTextContext_DEFINED
 #define GrAtlasTextContext_DEFINED
 
@@ skipping 175 matching lines @@
         // all glyph / vertex offsets are into these pools.
         unsigned char* fVertices;
         GrGlyph** fGlyphs;
         Run* fRuns;
         GrMemoryPool* fPool;
         SkMaskFilter::BlurRec fBlurRec;
         StrokeInfo fStrokeInfo;
         SkTArray<BigGlyph> fBigGlyphs;
         Key fKey;
         SkMatrix fViewMatrix;
-#ifdef SK_DEBUG
-        mutable SkScalar fTotalXError;
-        mutable SkScalar fTotalYError;
-#endif
         SkColor fPaintColor;
         SkScalar fX;
         SkScalar fY;
 
         // We can reuse distance field text, but only if the new viewmatrix would not result in
         // a mip change.  Because there can be multiple runs in a blob, we track the overall
         // maximum minimum scale, and minimum maximum scale, we can support before we need to regen
         SkScalar fMaxMinScale;
         SkScalar fMinMaxScale;
         int fRunCount;
@@ skipping 152 matching lines @@
     bool fEnableDFRendering;
     SkAutoTUnref<DistanceAdjustTable> fDistanceAdjustTable;
 
     friend class GrTextBlobCache;
     friend class BitmapTextBatch;
 
     typedef GrTextContext INHERITED;
 };
 
 #endif