Revert of Revert of Fix SkTextBlob offset semantics.

src/gpu/GrBitmapTextContext.cpp

Index: src/gpu/GrBitmapTextContext.cpp
diff --git a/src/gpu/GrBitmapTextContext.cpp b/src/gpu/GrBitmapTextContext.cpp
index 421051752615c4f32f89281262bff40b69b69777..d9a6b0eb9af3794abe25ca562d9f27ed35ec4cac 100755
--- a/src/gpu/GrBitmapTextContext.cpp
+++ b/src/gpu/GrBitmapTextContext.cpp
@@ -269,8 +269,8 @@
 
 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);
 
@@ -294,7 +294,7 @@
 
     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()) {