Revert "Make GPU backend triangulate rects such that they are rendered as tri strips rather than tri fans."

This reverts commit fa2d604a7ded95a3ace905519b476129cd0fffcb.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Make GPU backend triangulate rects such that they are rendered as tri strips rather than tri fans.
> 
> Right now when we turn rects into quads we use a vertex order compatible with a tri fan rather than a tri strip.
> 
> I wanted it to be the case that the same code could be used to generate a non-indexed mesh for a single rect or indexed using the quad index buffer when batching. Triangle fanning is not available in all APIS (e.g. is emulated in ANGLE and not supported in Metal) so it seems better to use a triangle strip over a fan in the single rect case.
> 
> 
> Change-Id: I31eebd794e7328f4b39e3ec3377bf2ec556360ca
> Reviewed-on: https://skia-review.googlesource.com/60081
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

TBR=bsalomon@google.com,robertphillips@google.com

Change-Id: I7c4c23aa418da09c9708b28cce64ab58e282dd3a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/60683
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/src/core/SkMatrixPriv.h b/src/core/SkMatrixPriv.h
index 47a1d5f287..ee6f8a153d 100644
--- a/src/core/SkMatrixPriv.h
+++ b/src/core/SkMatrixPriv.h
@@ -66,7 +66,7 @@ public:
         }
     }
 
-    static void SetMappedRectTriStrip(const SkMatrix& mx, const SkRect& rect, SkPoint quad[4]) {
+    static void SetMappedRectFan(const SkMatrix& mx, const SkRect& rect, SkPoint quad[4]) {
         SkMatrix::TypeMask tm = mx.getType();
         SkScalar l = rect.fLeft;
         SkScalar t = rect.fTop;
@@ -88,9 +88,12 @@ public:
                 r = sx * r + tx;
                 b = sy * b + ty;
             }
-            quad[0].setRectTriStrip(l, t, r, b, sizeof(SkPoint));
+            quad[0].set(l, t);
+            quad[1].set(l, b);
+            quad[2].set(r, b);
+            quad[3].set(r, t);
         } else {
-            quad[0].setRectTriStrip(l, t, r, b, sizeof(SkPoint));
+            quad[0].setRectFan(l, t, r, b);
             mx.mapPoints(quad, quad, 4);
         }
     }