use the correct rowBytes so Debug build doesn't assert

BUG=skia:2378
R=reed@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/235453002

git-svn-id: http://skia.googlecode.com/svn/trunk@14163 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/bench_playback.cpp b/tools/bench_playback.cpp
index 198e1f0..b5dc57b 100644
--- a/tools/bench_playback.cpp
+++ b/tools/bench_playback.cpp
@@ -28,8 +28,10 @@
     SkRecorder recorder(SkRecorder::kWriteOnly_Mode, &record, src.width(), src.height());
     src.draw(&recorder);
 
-    SkAutoTDelete<SkCanvas> canvas(
-        SkCanvas::NewRasterDirectN32(src.width(), src.height(), scratch, 0));
+    SkAutoTDelete<SkCanvas> canvas(SkCanvas::NewRasterDirectN32(src.width(),
+                                                                src.height(),
+                                                                scratch,
+                                                                src.width() * sizeof(SkPMColor)));
     canvas->clipRect(SkRect::MakeWH(SkIntToScalar(FLAGS_tile), SkIntToScalar(FLAGS_tile)));
 
     const SkMSec start = SkTime::GetMSecs();