Fix SkTextBlob offset semantics.

src/gpu/GrBitmapTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBitmapTextContext.h"
 #include "GrAtlas.h"
 #include "GrDrawTarget.h"
@@ skipping 251 matching lines @@
 
         fx += glyph.fAdvanceX;
         fy += glyph.fAdvanceY;
     }
 
     this->finish();
 }
 
 void GrBitmapTextContext::drawPosText(const GrPaint& paint, const SkPaint& skPaint,
                                       const char text[], size_t byteLength,
-                                      const SkScalar pos[], SkScalar constY,
-                                      int scalarsPerPosition) {
+                                      const SkScalar pos[], int scalarsPerPosition,
+                                      const SkPoint& offset) {
     SkASSERT(byteLength == 0 || text != NULL);
     SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);
 
     // nothing to draw
     if (text == NULL || byteLength == 0/* || fRC->isEmpty()*/) {
         return;
     }
 
     this->init(paint, skPaint);
 
     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
 
     SkAutoGlyphCache    autoCache(fSkPaint, &fDeviceProperties, &fContext->getMatrix());
     SkGlyphCache*       cache = autoCache.getCache();
     GrFontScaler*       fontScaler = GetGrFontScaler(cache);
 
     // store original matrix before we reset, so we can use it to transform positions
     SkMatrix ctm = fContext->getMatrix();
     GrContext::AutoMatrix  autoMatrix;
     autoMatrix.setIdentity(fContext, &fPaint);
 
     const char*        stop = text + byteLength;
     SkTextAlignProc    alignProc(fSkPaint.getTextAlign());
-    SkTextMapStateProc tmsProc(ctm, constY, scalarsPerPosition);
+    SkTextMapStateProc tmsProc(ctm, offset, scalarsPerPosition);
     SkFixed halfSampleX = 0, halfSampleY = 0;
 
     if (cache->isSubpixel()) {
         // maybe we should skip the rounding if linearText is set
         SkAxisAlignment baseline = SkComputeAxisAlignmentForHText(ctm);
 
         SkFixed fxMask = ~0;
         SkFixed fyMask = ~0;
         if (kX_SkAxisAlignment == baseline) {
             fyMask = 0;
@@ skipping 290 matching lines @@
         }
         // color comes after position.
         GrColor* colors = reinterpret_cast<GrColor*>(positions + 1);
         for (int i = 0; i < 4; ++i) {
            *colors = fPaint.getColor();
            colors = reinterpret_cast<GrColor*>(reinterpret_cast<intptr_t>(colors) + vertSize);
         }
     }
     fCurrVertex += 4;
 }