Histograms - Support histograms for Plugins, GPU

content/public/browser/histogram_fetcher.h

+// Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_HISTOGRAM_FETCHER_H_
+#define CONTENT_PUBLIC_BROWSER_HISTOGRAM_FETCHER_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/time.h"
+#include "content/common/content_export.h"
+
+class MessageLoop;
+
+namespace content {
+
+// Fetch histogram data asynchronously from the various child processes, into
+// the browser process. This method is used by the metrics services in
+// preparation for a log upload. It contacts all processes, and get them to
+// upload to the browser any/all changes to histograms.  When all changes have
+// been acquired, or when the wait time expires (whichever is sooner), post the
+// callback to the specified message loop. Note the callback is posted exactly
+// once.
+CONTENT_EXPORT void FetchHistogramsAsynchronously(MessageLoop* callback_thread,
+                                                  const base::Closure& callback,
+                                                  base::TimeDelta wait_time);
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_HISTOGRAM_FETCHER_H_