Fix cases of variable shadowing in samplecode/.

These were reviewed last year at http://review.skia.org/312480 but never
landed. Splitting into small chunks to land individually.

If we manage to fix all the existing cases of variable shadowing, we
could enable -Wshadow.

Change-Id: I53d04e5b2ffd7e170a8b10a6bacbc239c8b5e7ff
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/435720
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ravi Mistry <rmistry@google.com>
diff --git a/samplecode/SampleShadowUtils.cpp b/samplecode/SampleShadowUtils.cpp
index 2571c03..15199e2 100644
--- a/samplecode/SampleShadowUtils.cpp
+++ b/samplecode/SampleShadowUtils.cpp
@@ -171,9 +171,7 @@
         SkScalar dy = 0;
         SkTDArray<SkMatrix> matrices;
         matrices.push()->reset();
-        SkMatrix* m = matrices.push();
-        m->setRotate(33.f, 25.f, 25.f);
-        m->postScale(1.2f, 0.8f, 25.f, 25.f);
+        matrices.push()->setRotate(33.f, 25.f, 25.f).postScale(1.2f, 0.8f, 25.f, 25.f);
         SkPaint paint;
         paint.setColor(SK_ColorGREEN);
         paint.setAntiAlias(true);