Integrate Crashpad UMA

base/metrics/persistent_metrics_file_util.cc

+// 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.
+
+#include "base/metrics/persistent_metrics_file_util.h"
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/metrics/persistent_histogram_allocator.h"
+#include "base/metrics/persistent_memory_allocator.h"
+
+namespace base {
+
+void InitializeGlobalPersistentMetricsStorage(const base::FilePath& dir,
+                                              const char* metrics_name,
+                                              size_t size) {
+  // Metrics maps one file that we're going to use during this run (the
+  // "-active" one), and provides the previous one to the metrics system for for
+  // association with the previous run. On startup, we move the current -active
+  // to the base name, and then start this session on the -active one. Normally,
+  // when the browser starts it will read and delete the base name one, but in
+  // the case that something goes wrong, we will overwrite/delete any old one.
+  base::FilePath metrics_file =
+      dir.AppendASCII(metrics_name)
+          .AddExtension(PersistentMemoryAllocator::kFileExtension);
+  base::FilePath active_file =
+      dir.AppendASCII(metrics_name + std::string("-active"))
+          .AddExtension(PersistentMemoryAllocator::kFileExtension);
+
+  if (!base::ReplaceFile(active_file, metrics_file, nullptr))
+    base::DeleteFile(metrics_file, /*recursive=*/false);
+
+  base::GlobalHistogramAllocator::CreateWithFile(active_file, size, 0,
+                                                 metrics_name);
+
+  // Get the allocator that was just created and report result. Exit if the
+  // allocator could not be created.
+  base::GlobalHistogramAllocator* allocator =
+      base::GlobalHistogramAllocator::Get();
+  if (!allocator)
+    return;
+
+  // Create tracking histograms for the allocator and record storage file.
+  allocator->CreateTrackingHistograms(metrics_name);
+  allocator->SetPersistentLocation(active_file);
+}
+
+void CleanUpGlobalPersistentHistogramStorage() {
+  base::GlobalHistogramAllocator* allocator =
+      base::GlobalHistogramAllocator::Get();
+  if (!allocator)
+    return;
+
+  const base::FilePath& path = allocator->GetPersistentLocation();
+  if (path.empty())
+    return;
+
+  // Open (with delete) and then immediately close the file by going out of
+  // scope. This is the only cross-platform safe way to delete a file that may
+  // be open elsewhere. Open handles will continue to operate normally but
+  // new opens will not be possible.
+  base::File file(path, base::File::FLAG_OPEN | base::File::FLAG_READ |

[Mark Mentovai, 2016/09/13 21:34:06]

Ha, there’s a river here at column 24!

[scottmg, 2016/09/13 21:40:50]

Yeah, I was surprised by that too, but I guess clang-format is trying to avoid
it looking like a 3rd argument.

+                            base::File::FLAG_DELETE_ON_CLOSE);
+}
+
+}  // namespace base