Reland "Do not use sub-pixel positioning for source space"

This is a reland of 7b56b0ae3947eb0f9a782a2dc2c4145ef39644b9

Original change's description:
> Do not use sub-pixel positioning for source space
>
> Since the source space drawing modes call getGlyphMetrics with
> the point {0, 0}, just turn of sub-pixel positioning. This uses
> a more efficient code path in the strike
>
> Change-Id: I360f56e1eede776dfa82db6b780b88c1fda50d36
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/206701
> Reviewed-by: Ben Wagner <bungeman@google.com>
> Commit-Queue: Ben Wagner <bungeman@google.com>
> Commit-Queue: Herb Derby <herb@google.com>
> Auto-Submit: Herb Derby <herb@google.com>

Change-Id: I4f5305990765e280930f93b25c049f6df198dc10
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/206912
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/src/gpu/text/GrTextContext.cpp b/src/gpu/text/GrTextContext.cpp
index 7fb6a71..5446edd 100644
--- a/src/gpu/text/GrTextContext.cpp
+++ b/src/gpu/text/GrTextContext.cpp
@@ -172,7 +172,9 @@
     dfFont.setEdging(SkFont::Edging::kAntiAlias);
     dfFont.setForceAutoHinting(false);
     dfFont.setHinting(kNormal_SkFontHinting);
-    dfFont.setSubpixel(true);
+
+    // The sub-pixel position will always happen when transforming to the screen.
+    dfFont.setSubpixel(false);
     return dfFont;
 }