Tweak SkPictureShader's tile semantics.

src/core/SkPictureShader.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPictureShader.h"
 
 #include "SkBitmap.h"
@@ skipping 167 matching lines @@
     if (!SkResourceCache::Find(key, BitmapShaderRec::Visitor, &tileShader)) {
         SkBitmap bm;
         bm.setInfo(SkImageInfo::MakeN32Premul(tileSize));
         if (!cache_try_alloc_pixels(&bm)) {
             return NULL;
         }
         bm.eraseColor(SK_ColorTRANSPARENT);
 
         SkCanvas canvas(bm);
         canvas.scale(tileScale.width(), tileScale.height());
-        canvas.translate(fTile.x(), fTile.y());
+        canvas.translate(-fTile.x(), -fTile.y());
         canvas.drawPicture(fPicture);
 
         SkMatrix shaderMatrix = this->getLocalMatrix();
         shaderMatrix.preScale(1 / tileScale.width(), 1 / tileScale.height());
         tileShader.reset(CreateBitmapShader(bm, fTmx, fTmy, &shaderMatrix));
 
         SkResourceCache::Add(SkNEW_ARGS(BitmapShaderRec, (key, tileShader.get(), bm.getSize())));
     }
 
     return tileShader.detach();
@@ skipping 89 matching lines @@
     }
     return bitmapShader->asFragmentProcessor(context, paint, NULL, paintColor, fp);
 }
 #else
 bool SkPictureShader::asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix*, GrColor*,
                                           GrFragmentProcessor**) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return false;
 }
 #endif