Add WriteBitmapToPng to EmbedderTest.

This is a util method to output the png to a file for visually
validating the result of an embedder test. Once validated, the
md5 can be considered correct.

Bug: pdfium:981
Change-Id: I544dfbf2e85295e6ca2cdf48d1bc3f0bd5f415e9
Reviewed-on: https://pdfium-review.googlesource.com/22990
Reviewed-by: Nicolás Peña Moreno <npm@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/BUILD.gn b/BUILD.gn
index f4e5fe9e44..60c2e42f7a 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -2926,6 +2926,7 @@ test("pdfium_embeddertests") {
     "testing/range_set.h",
   ]
   deps = [
+    ":image_diff",
     ":pdfium",
     ":test_support",
     "//testing/gmock",