* Extended skdiff to report alpha channel differences.
* Created a tools/tests/rebaseline.sh to copy output-actual into output-expected.
* Sample results are available here: http://www.corp.google.com/~rmistry/skia/gm-playback-windows/images-skdiff/
Review URL: https://codereview.appspot.com/7038048

git-svn-id: http://skia.googlecode.com/svn/trunk@7003 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/skdiff_html.cpp b/tools/skdiff_html.cpp
index 85d8777..d83b736 100644
--- a/tools/skdiff_html.cpp
+++ b/tools/skdiff_html.cpp
@@ -124,6 +124,19 @@
         if (diff.fFractionDifference < 0.01) {
             print_pixel_count(stream, diff);
         }
+        stream->writeText("<br>");
+        if (static_cast<int>(diff.fAverageMismatchA) > 0) {
+          stream->writeText("<br>Average alpha channel mismatch ");
+          stream->writeDecAsText(static_cast<float>(diff.fAverageMismatchA));
+        }
+
+        stream->writeText("<br>Max alpha channel mismatch ");
+        stream->writeDecAsText(static_cast<int>(diff.fMaxMismatchA));
+
+        stream->writeText("<br>Total alpha channel mismatch ");
+        stream->writeDecAsText(static_cast<int>(diff.fTotalMismatchA));
+
+        stream->writeText("<br>");
         stream->writeText("<br>Average color mismatch ");
         stream->writeDecAsText(static_cast<int>(MAX3(diff.fAverageMismatchR,
                                                      diff.fAverageMismatchG,