Properly retrieve memory block in SkTextUtils

Fixes a crash when calling SkTextUtils::GetPath with empty text
(or otherwise gets no glyphs to draw).

Change-Id: I11711df354be0045ab348bdd7e6cc0c01d3a4e90
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209200
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Martin Vejdarski <martin@mainframe.co.uk>

src/utils/SkTextUtils.cpp

diff --git a/src/utils/SkTextUtils.cpp b/src/utils/SkTextUtils.cpp
index 3973497..8596a0f 100644
--- a/src/utils/SkTextUtils.cpp
+++ b/src/utils/SkTextUtils.cpp
@@ -28,12 +28,12 @@
                           SkScalar x, SkScalar y, const SkFont& font, SkPath* path) {
     SkAutoToGlyphs ag(font, text, length, encoding);
     SkAutoTArray<SkPoint> pos(ag.count());
-    font.getPos(ag.glyphs(), ag.count(), &pos[0], {x, y});
+    font.getPos(ag.glyphs(), ag.count(), pos.get(), {x, y});
 
     struct Rec {
         SkPath* fDst;
         const SkPoint* fPos;
-    } rec = { path, &pos[0] };
+    } rec = { path, pos.get() };
 
     path->reset();
     font.getPaths(ag.glyphs(), ag.count(), [](const SkPath* src, const SkMatrix& mx, void* ctx) {