Fix memory init in SkCanvasVideoRendererTest.

BUG=369375

Review URL: https://codereview.chromium.org/325493002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275647 0039d316-1c4b-4281-b951-d872f2087c98

media/filters/skcanvas_video_renderer_unittest.cc

@@ -79,6 +79,7 @@ class SkCanvasVideoRendererTest : public testing::Test {
 static SkBitmap AllocBitmap(int width, int height) {
   SkBitmap bitmap;
   bitmap.allocPixels(SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
+  bitmap.eraseColor(0);
   return bitmap;
 }