Fix SkTextBlob offset semantics.

src/gpu/SkGpuDevice.cpp

Index: src/gpu/SkGpuDevice.cpp
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 7ce3446b72e59289f8741fd20bf8355ae3bfd4a3..d2df8518c25801f3f53f984ed35e7f9aeb388d3b 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -1713,10 +1713,9 @@ void SkGpuDevice::drawText(const SkDraw& draw, const void* text,
     }
 }
 
-void SkGpuDevice::drawPosText(const SkDraw& draw, const void* text,
-                             size_t byteLength, const SkScalar pos[],
-                             SkScalar constY, int scalarsPerPos,
-                             const SkPaint& paint) {
+void SkGpuDevice::drawPosText(const SkDraw& draw, const void* text, size_t byteLength,
+                              const SkScalar pos[], int scalarsPerPos,
+                              const SkPoint& offset, const SkPaint& paint) {
     GR_CREATE_TRACE_MARKER_CONTEXT("SkGpuDevice::drawPosText", fContext);
     CHECK_SHOULD_DRAW(draw, false);
 
@@ -1727,7 +1726,7 @@ void SkGpuDevice::drawPosText(const SkDraw& draw, const void* text,
         SkDEBUGCODE(this->validate();)
 
         fMainTextContext->drawPosText(grPaint, paint, (const char *)text, byteLength, pos,
-                                      constY, scalarsPerPos);
+                                      scalarsPerPos, offset);
     } else if (fFallbackTextContext && fFallbackTextContext->canDraw(paint)) {
         GrPaint grPaint;
         SkPaint2GrPaintShader(this->context(), paint, true, &grPaint);
@@ -1735,10 +1734,9 @@ void SkGpuDevice::drawPosText(const SkDraw& draw, const void* text,
         SkDEBUGCODE(this->validate();)
 
         fFallbackTextContext->drawPosText(grPaint, paint, (const char *)text, byteLength, pos,
-                                          constY, scalarsPerPos);
+                                          scalarsPerPos, offset);
     } else {
-        draw.drawPosText_asPaths((const char*)text, byteLength, pos, constY,
-                                 scalarsPerPos, paint);
+        draw.drawPosText_asPaths((const char*)text, byteLength, pos, scalarsPerPos, offset, paint);
     }
 }