DM: use SkBitmap::reset()

BUG=skia:

Review URL: https://codereview.chromium.org/1310373004

1 files changed, 1 insertions, 1 deletions

diff --git a/dm/DM.cpp b/dm/DM.cpp
index 8537313cf3..b93f9d8078 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -493,7 +493,7 @@ static bool dump_png(SkBitmap bitmap, const char* path, const char* md5) {
     }
 
     // We don't need bitmap anymore.  Might as well drop our ref.
-    bitmap = SkBitmap();
+    bitmap.reset();
 
     FILE* f = fopen(path, "w");
     if (!f) { return false; }