Use SkTextBlob for nvpr color bitmap fallbacks

src/gpu/GrStencilAndCoverTextContext.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrStencilAndCoverTextContext_DEFINED
 #define GrStencilAndCoverTextContext_DEFINED
 
@@ skipping 27 matching lines @@
                     const SkMatrix& viewMatrix,
                     const char text[], size_t byteLength,
                     SkScalar x, SkScalar y, const SkIRect& regionClipBounds) override;
     void onDrawPosText(GrDrawContext*, GrRenderTarget*,
                        const GrClip&, const GrPaint&, const SkPaint&,
                        const SkMatrix& viewMatrix,
                        const char text[], size_t byteLength,
                        const SkScalar pos[], int scalarsPerPosition,
                        const SkPoint& offset, const SkIRect& regionClipBounds) override;
 
+    class FallbackBlobBuilder;
+
     class TextRun {
     public:
         TextRun(const SkPaint& fontAndStroke);
         ~TextRun();
 
         void setText(const char text[], size_t byteLength, SkScalar x, SkScalar y,
                      GrContext*, const SkSurfaceProps*);
 
         void setPosText(const char text[], size_t byteLength,
                         const SkScalar pos[], int scalarsPerPosition, const SkPoint& offset,
                         GrContext*, const SkSurfaceProps*);
 
         void draw(GrDrawContext*, GrRenderTarget*, const GrClip&, const GrPaint&, const SkMatrix&,
                   const SkIRect& regionClipBounds, GrTextContext* fallbackTextContext,
                   const SkPaint& originalSkPaint) const;
 
     private:
         GrPathRange* createGlyphs(GrContext*, SkGlyphCache*);
 
-        void appendGlyph(const SkGlyph&, const SkPoint&);
+        void appendGlyph(const SkGlyph&, const SkPoint&, FallbackBlobBuilder*);
 
         GrStrokeInfo                     fStroke;
         SkPaint                          fFont;
         SkScalar                         fTextRatio;
         float                            fTextInverseRatio;
         SkMatrix                         fLocalMatrix;
         bool                             fUsingRawGlyphPaths;
         SkAutoTUnref<GrPathRangeDraw>    fDraw;
-        SkSTArray<32, uint16_t, true>    fFallbackIndices;
-        SkSTArray<32, SkPoint, true>     fFallbackPositions;
+        SkAutoTUnref<const SkTextBlob>   fFallbackTextBlob;
     };
 
     typedef GrTextContext INHERITED;
 };
 
 #endif