Histograms - Support histograms for Plugins, GPU

content/public/browser/histogram_controller.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_CONTROLLER_H_
+#define CONTENT_PUBLIC_BROWSER_HISTOGRAM_CONTROLLER_H_
+
+#include <set>
+#include <string>
+
+#include "base/metrics/histogram.h"
+#include "content/common/content_export.h"
+
+
+namespace base {
+class DictionaryValue;
+}
+
+namespace content {
+
+class HistogramSubscriber;
+
+// HistogramController is used on the browser process to collect histogram data.
+// Only the browser UI thread is allowed to interact with the
+// HistogramController object.
+class CONTENT_EXPORT HistogramController {
+ public:
+  // Returns the HistogramController object for the current process, or NULL if
+  // none.
+  static HistogramController* GetInstance();
+
+  virtual ~HistogramController() {}
+
+  // Register the subscriber so that it will be called when for example
+  // OnHistogramDataCollected is returning histogram data from a child process.
+  // This is called on UI thread.
+  virtual void Register(HistogramSubscriber* subscriber) = 0;
+
+  // Unregister the subscriber so that it will not be called when for example
+  // OnHistogramDataCollected is returning histogram data from a child process.
+  // Safe to call even if caller is not the current subscriber.
+  virtual void Unregister(const HistogramSubscriber* subscriber) = 0;
+
+  // Contact all processes and get their histogram data.
+  virtual void GetHistogramData(int sequence_number) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_HISTOGRAM_CONTROLLER_H_