Histograms - Support histograms for Plugins, GPU

content/common/child_histogram_message_filter.h

Index: content/common/child_histogram_message_filter.h
===================================================================
--- content/common/child_histogram_message_filter.h	(revision 0)
+++ content/common/child_histogram_message_filter.h	(working copy)
@@ -0,0 +1,65 @@
+// 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_COMMOM_CHILD_HISTOGRAM_MESSAGE_FILTER_H_
+#define CONTENT_COMMOM_CHILD_HISTOGRAM_MESSAGE_FILTER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_flattener.h"
+#include "base/metrics/histogram_snapshot_manager.h"
+#include "ipc/ipc_channel_proxy.h"
+
+class MessageLoop;
+
+namespace content {
+
+class ChildHistogramMessageFilter : public base::HistogramFlattener,
+                                    public IPC::ChannelProxy::MessageFilter {
+ public:
+  ChildHistogramMessageFilter();
+
+  // IPC::ChannelProxy::MessageFilter implementation.
+  virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
+  virtual void OnFilterRemoved() OVERRIDE;
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  void SendHistograms(int sequence_number);
+
+  // HistogramFlattener interface (override) methods.
+  virtual void RecordDelta(const base::Histogram& histogram,
+                           const base::Histogram::SampleSet& snapshot) OVERRIDE;
+  virtual void InconsistencyDetected(int problem) OVERRIDE;
+  virtual void UniqueInconsistencyDetected(int problem) OVERRIDE;
+  virtual void SnapshotProblemResolved(int amount) OVERRIDE;
+
+ private:
+  typedef std::vector<std::string> HistogramPickledList;
+
+  virtual ~ChildHistogramMessageFilter();
+
+  // Message handlers.
+  virtual void OnGetChildHistogramData(int sequence_number);
+
+  // Extract snapshot data and then send it off the the Browser process.
+  // Send only a delta to what we have already sent.
+  void UploadAllHistrograms(int sequence_number);
+
+  IPC::Channel* channel_;
+
+  // Collection of histograms to send to the browser.
+  HistogramPickledList pickled_histograms_;
+
+  // |histogram_snapshot_manager_| prepares histogram deltas for transmission.
+  base::HistogramSnapshotManager histogram_snapshot_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChildHistogramMessageFilter);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMOM_CHILD_HISTOGRAM_MESSAGE_FILTER_H_