SkCanvas: Helpers for draw{Point,Line,Circle}

Change-Id: Ie9c7d3b8f01aee435563b23b7d27f098f07dd287
Reviewed-on: https://skia-review.googlesource.com/16909
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/samplecode/SampleHairline.cpp b/samplecode/SampleHairline.cpp
index 169804d..fe9e07c 100644
--- a/samplecode/SampleHairline.cpp
+++ b/samplecode/SampleHairline.cpp
@@ -77,7 +77,7 @@
     for (int i = 0; i < 400; i++) {
         generate_pts(pts, N, WIDTH, HEIGHT);
 
-        canvas->drawLine(pts[0].fX, pts[0].fY, pts[1].fX, pts[1].fY, paint);
+        canvas->drawLine(pts[0], pts[1], paint);
         if (!check_bitmap_margin(bm, MARGIN)) {
             SkDebugf("---- hairline failure (%g %g) (%g %g)\n",
                      pts[0].fX, pts[0].fY, pts[1].fX, pts[1].fY);