Revert of Revert of Fix SkTextBlob offset semantics.

include/pdf/SkPDFDevice.h

Index: include/pdf/SkPDFDevice.h
diff --git a/include/pdf/SkPDFDevice.h b/include/pdf/SkPDFDevice.h
index 0bfbc36d1ae842bb5c46c41dca35779a7bd8f119..0ada5312aec27686b14c6d73b372d34485fefc78 100644
--- a/include/pdf/SkPDFDevice.h
+++ b/include/pdf/SkPDFDevice.h
@@ -98,8 +98,8 @@
     virtual void drawText(const SkDraw&, const void* text, size_t len,
                           SkScalar x, SkScalar y, const SkPaint&) SK_OVERRIDE;
     virtual void drawPosText(const SkDraw&, const void* text, size_t len,
-                             const SkScalar pos[], SkScalar constY,
-                             int scalarsPerPos, const SkPaint&) SK_OVERRIDE;
+                             const SkScalar pos[], int scalarsPerPos,
+                             const SkPoint& offset, const SkPaint&) SK_OVERRIDE;
     virtual void drawTextOnPath(const SkDraw&, const void* text, size_t len,
                                 const SkPath& path, const SkMatrix* matrix,
                                 const SkPaint& paint) SK_OVERRIDE;