Persist setup metrics and have Chrome report them during UMA upload.

chrome/browser/metrics/chrome_setup_metrics_provider.h

+// Copyright 2015 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 CHROME_BROWSER_METRICS_CHROME_SETUP_METRICS_PROVIDER_H_
+#define CHROME_BROWSER_METRICS_CHROME_SETUP_METRICS_PROVIDER_H_
+
+#include <atomic>
+
+#include "base/basictypes.h"
+#include "base/files/file_path.h"
+#include "base/gtest_prod_util.h"
+#include "base/memory/scoped_ptr.h"
+#include "components/metrics/metrics_provider.h"
+
+namespace base {
+

[Alexei Svitkine (slow), 2015/12/21 16:54:53]

Nit: No need for blank lines within namespace for forward decls.

[bcwhite, 2015/12/22 12:51:30]

Done.

+class MemoryMappedFile;
+class PersistentMemoryAllocator;
+
+};

[Alexei Svitkine (slow), 2015/12/21 16:54:53]

Nit: No ;

[bcwhite, 2015/12/22 12:51:30]

Done.

+
+namespace metrics {
+
+class MetricsService;
+
+};
+
+class PrefService;
+
+// ChromeSetupMetricsProvider gathers and logs Chrome-specific setup-
+// related metrics reported by setup.exe and saved to a file on disk.
+class ChromeSetupMetricsProvider
+    : public metrics::MetricsProvider {
+ public:
+  ChromeSetupMetricsProvider(metrics::MetricsService* metrics_service,
+                             PrefService* local_state);
+  ~ChromeSetupMetricsProvider() override;
+
+  // metrics::MetricsDataProvider:
+  void OnDidCreateMetricsLog() override;
+
+ private:
+  friend class ChromeSetupMetricsProviderTest;
+  FRIEND_TEST_ALL_PREFIXES(ChromeSetupMetricsProviderTest, AccessMetrics);
+
+  base::FilePath GetSetupMetricsFile();
+  void CheckForSetupMetrics();
+
+  // Explicitly set the directory containing this program. (for testing)
+  void SetProgramDirectory(const base::FilePath& dir);
+
+  std::atomic<bool> metrics_found_;
+  metrics::MetricsService* metrics_service_;
+  PrefService* pref_service_;
+  base::FilePath program_directory_;
+  scoped_ptr<base::MemoryMappedFile> metrics_file_;
+  scoped_ptr<base::PersistentMemoryAllocator> metrics_allocator_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeSetupMetricsProvider);
+};
+
+#endif  // CHROME_BROWSER_METRICS_CHROME_SETUP_METRICS_PROVIDER_H_