bootstat: Track record inconsistencies w/ a debug metric, bootstat_mtime_matches_content.

Fixed a file descriptor leak while I was in here.

Bug: 27550578
Change-Id: I8e252e4f5bb3c4e2ae96a1560fbb32ae636722a0
diff --git a/bootstat/histogram_logger.cpp b/bootstat/histogram_logger.cpp
new file mode 100644
index 0000000..e3aad28
--- /dev/null
+++ b/bootstat/histogram_logger.cpp
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "histogram_logger.h"
+
+#include <cstdlib>
+#include <memory>
+#include <android-base/logging.h>
+#include <log/log.h>
+#include "event_log_list_builder.h"
+
+namespace bootstat {
+
+void LogHistogram(const std::string& event, int32_t data) {
+  LOG(INFO) << "Logging histogram: " << event << " " << data;
+
+  EventLogListBuilder log_builder;
+  log_builder.Append(event);
+  log_builder.Append(data);
+
+  std::unique_ptr<uint8_t[]> log;
+  size_t size;
+  log_builder.Release(&log, &size);
+
+  android_bWriteLog(HISTOGRAM_LOG_TAG, log.get(), size);
+}
+
+}  // namespace bootstat
\ No newline at end of file