Histograms - Support histograms for Plugins, GPU

content/public/browser/histogram_subscriber.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_SUBSCRIBER_H_
+#define CONTENT_PUBLIC_BROWSER_HISTOGRAM_SUBSCRIBER_H_
+
+#include <string>
+#include <vector>
+
+#include "content/common/content_export.h"
+#include "content/public/common/process_type.h"
+
+namespace content {
+
+// Objects interested in receiving histograms derive from HistogramSubscriber.
+class CONTENT_EXPORT HistogramSubscriber {
+ public:
+  virtual ~HistogramSubscriber() {}
+
+  // Send number of pending processes to subscriber. |end| is set to true if it
+  // is the last time. This is called on the UI thread.
+  virtual void OnPendingProcesses(int sequence_number,
+                                  int pending_processes,
+                                  bool end) = 0;
+
+  // Send |histogram| back to subscriber.
+  // This is called on the UI thread.
+  virtual void OnHistogramDataCollected(
+      int sequence_number,
+      const std::vector<std::string>& pickled_histograms,
+      ProcessType process_type) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_HISTOGRAM_SUBSCRIBER_H_