When running DM, write test failures to json.

dm/DMJsonWriter.cpp

Index: dm/DMJsonWriter.cpp
diff --git a/dm/DMJsonWriter.cpp b/dm/DMJsonWriter.cpp
index f86264715bcd65367eb9c1430e798fa33f495a1a..bc87e68d876b9b28acdd51ad91648a859e6186e7 100644
--- a/dm/DMJsonWriter.cpp
+++ b/dm/DMJsonWriter.cpp
@@ -24,6 +24,14 @@ void JsonWriter::AddBitmapResult(const BitmapResult& result) {
     gBitmapResults.push_back(result);
 }
 
+SkTArray<skiatest::Failure> gFailures;
+SK_DECLARE_STATIC_MUTEX(gFailureLock);
+
+void JsonWriter::AddTestFailure(const skiatest::Failure& failure) {
+    SkAutoMutexAcquire lock(gFailureLock);
+    gFailures.push_back(failure);
+}
+
 void JsonWriter::DumpJson() {
     if (FLAGS_writePath.isEmpty()) {
         return;
@@ -52,6 +60,21 @@ void JsonWriter::DumpJson() {
         }
     }
 
+    {
+        const char* test_results = "test_results";

[scroggo, 2014/11/05 20:40:17]

This block writes out the test results in the format listed in the change
description. I'm not attached to that format, so if something would be better
for the bots or a human to read, please let me know.

[mtklein, 2014/11/06 15:24:05]

It's probably OK to just write "test_results" where it's used. :)

[mtklein, 2014/11/06 15:24:05]

You're adding this, so you tell us what's a good format.  No humans or bots
currently look at this, because it doesn't exist. :)

[scroggo, 2014/11/06 16:52:32]

I was being cautious since I used it twice. I've removed one of those uses, so
there's no reason for it anymore.

+        SkAutoMutexAcquire lock(gFailureLock);
+        root[test_results]["num_failures"] = gFailures.count();

[mtklein, 2014/11/06 15:24:05]

Isn't this redundant?  It's sort of clear from the length of the failures list.

[scroggo, 2014/11/06 16:52:32]

It is redundant, but I thought maybe it's easier to have one place to look than
to count? That said, what we really care about is that there exists some
failure, rather than the precise number. I'll remove.

+        for (int i = 0; i < gFailures.count(); i++) {
+            Json::Value result;
+            result["file_name"]     = gFailures[i].fileName.c_str();
+            result["line_no"]       = gFailures[i].lineNo;
+            result["condition"]     = gFailures[i].condition.c_str();
+            result["message"]       = gFailures[i].message.c_str();
+
+            root[test_results]["failures"].append(result);
+        }
+    }
+
     SkString path = SkOSPath::Join(FLAGS_writePath[0], "dm.json");
     SkFILEWStream stream(path.c_str());
     stream.writeText(Json::StyledWriter().write(root).c_str());