Add some SkTextBlob builder tests.

include/core/SkTextBlob.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 SkTextBlob_DEFINED
 #define SkTextBlob_DEFINED
 
@@ skipping 51 matching lines @@
         uint32_t         posStart;   // index into fPosBuffer
         SkPoint          offset;     // run offset (unsued for fully positioned glyphs)
         SkPaint          font;
         GlyphPositioning positioning;
     };
 
     SkTextBlob(uint16_t* glyphs, SkScalar* pos, const SkTArray<Run>* runs, const SkRect& bounds);
 
     friend class SkCanvas;
     friend class SkTextBlobBuilder;
+    friend class TextBlobTester;
 
     const SkAutoTMalloc<uint16_t>       fGlyphBuffer;
     const SkAutoTMalloc<SkScalar>       fPosBuffer;
 
     // SkTArray required here for run font destruction.
     SkAutoTDelete<const SkTArray<Run> > fRuns;
     const SkRect                        fBounds;
 
     mutable uint32_t                    fUniqueID;
 
@@ skipping 88 matching lines @@
     SkTDArray<SkScalar>        fPosBuffer;
     SkTArray<SkTextBlob::Run>* fRuns;
 
     SkRect                     fBounds;
     bool                       fDeferredBounds;
 
     RunBuffer                  fCurrentRunBuffer;
 };
 
 #endif // SkTextBlob_DEFINED