Histograms - Support histograms for Plugins, GPU

content/browser/histogram_controller_impl.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_BROWSER_HISTOGRAM_CONTROLLER_IMPL_H_
+#define CONTENT_BROWSER_HISTOGRAM_CONTROLLER_IMPL_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/singleton.h"
+#include "base/process.h"
+#include "content/common/content_export.h"
+#include "content/public/browser/histogram_controller.h"
+#include "content/public/common/process_type.h"
+
+namespace content {
+
+// HistogramController's implementation.
+class HistogramControllerImpl : public HistogramController {
+ public:
+  static HistogramControllerImpl* GetInstance();
+
+  // Normally instantiated when the child process is launched. Only one instance
+  // should be created per process.
+  HistogramControllerImpl();
+  virtual ~HistogramControllerImpl();
+
+  // Notify the |subscriber_| that it should expect at least |pending_processes|
+  // additional calls to OnHistogramDataCollected().  OnPendingProcess() may be
+  // called repeatedly; the last call will have |end| set to true, indicating
+  // that there is no longer a possibility for the count of pending processes to
+  // increase.  This is called on the UI thread.
+  void OnPendingProcesses(int sequence_number, int pending_processes, bool end);
+
+  // Send the |histogram| back to the |subscriber_|.
+  // This can be called from any thread.
+  void OnHistogramDataCollected(
+      int sequence_number,
+      const std::vector<std::string>& pickled_histograms,
+      content::ProcessType process_type);
+
+  // HistogramController implementation:
+  virtual void Register(HistogramSubscriber* subscriber) OVERRIDE;
+  virtual void Unregister(const HistogramSubscriber* subscriber) OVERRIDE;
+  virtual void GetHistogramData(int sequence_number) OVERRIDE;
+
+ private:
+  friend struct DefaultSingletonTraits<HistogramControllerImpl>;
+
+  // Contact child processes and get their histogram data.
+  void GetHistogramDataFromChildProcesses(int sequence_number);
+
+  HistogramSubscriber* subscriber_;
+
+  DISALLOW_COPY_AND_ASSIGN(HistogramControllerImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_HISTOGRAM_CONTROLLER_IMPL_H_