Read Chrome build ID and store it in leak reports

components/metrics/leak_detector/gnu_build_id_reader.h

Index: components/metrics/leak_detector/gnu_build_id_reader.h
diff --git a/components/metrics/leak_detector/gnu_build_id_reader.h b/components/metrics/leak_detector/gnu_build_id_reader.h
new file mode 100644
index 0000000000000000000000000000000000000000..2445f55778b2bc983d00a9b885960666023e2871
--- /dev/null
+++ b/components/metrics/leak_detector/gnu_build_id_reader.h
@@ -0,0 +1,35 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_METRICS_LEAK_DETECTOR_GNU_BUILD_ID_READER_H_
+#define COMPONENTS_METRICS_LEAK_DETECTOR_GNU_BUILD_ID_READER_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+namespace metrics {
+namespace leak_detector {
+
+// Reads the build ID from the GNU build notes and stores it internally. Since
+// the build ID is not expected to change over a process, the stored build ID
+// can be referenced repeatedly.
+class GNUBuildIDReader {
+ public:
+  GNUBuildIDReader();
+  ~GNUBuildIDReader();
+
+  // Reads the build ID and stores it in |build_id_|.
+  void ReadBuildID();

[Will Harris, 2016/07/18 22:03:53]

why not just a static function to return the build_id?

[Simon Que, 2016/07/19 00:29:34]

Done.

+
+  const std::vector<uint8_t>& build_id() const { return build_id_; }

[Will Harris, 2016/07/18 22:03:53]

DCHECK if the build_id_ hasn't been read?

[Simon Que, 2016/07/19 00:29:34]

Done.

+
+ private:
+  std::vector<uint8_t> build_id_;
+};
+
+}  // namespace leak_detector
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_LEAK_DETECTOR_GNU_BUILD_ID_READER_H_