Initial support for Renderer Side Histograms...

chrome/renderer/renderer_histogram_snapshots.h

Index: chrome/renderer/renderer_histogram_snapshots.h
===================================================================
--- chrome/renderer/renderer_histogram_snapshots.h	(revision 0)
+++ chrome/renderer/renderer_histogram_snapshots.h	(revision 0)
@@ -0,0 +1,54 @@
+// Copyright (c) 2006-2008 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 CHROME_RENDERER_HISTOGRAM_SNAPSHOTS_H_
+#define CHROME_RENDERER_HISTOGRAM_SNAPSHOTS_H_
+
+#include <list>
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/histogram.h"
+#include "base/process.h"
+#include "base/scoped_ptr.h"
+#include "base/task.h"
+
+class RendererHistogramSnapshots {
+ public:
+  RendererHistogramSnapshots();
+
+  ~RendererHistogramSnapshots() {}
+
+  // Send the histogram data.
+  void SendHistograms();
+
+  // Maintain a map of histogram names to the sample stats we've sent.
+  typedef std::map<std::string, Histogram::SampleSet> LoggedSampleMap;
+  typedef std::vector<std::string> HistogramPickledList;
+
+ private:
+  // Extract snapshot data and then send it off the the Browser process.
+  // Send only a delta to what we have already sent.
+  void UploadAllHistrograms();
+  void UploadHistrogram(const Histogram& histogram,
+                        HistogramPickledList* histograms);
+  void UploadHistogramDelta(const Histogram& histogram,
+                            const Histogram::SampleSet& snapshot,
+                            HistogramPickledList* histograms);
+
+  ScopedRunnableMethodFactory<RendererHistogramSnapshots>
+      renderer_histogram_snapshots_factory_;
+
+  // For histograms, record what we've already logged (as a sample for each
+  // histogram) so that we can send only the delta with the next log.
+  LoggedSampleMap logged_samples_;
+
+  DISALLOW_COPY_AND_ASSIGN(RendererHistogramSnapshots);
+};
+
+#endif  // CHROME_RENDERER_HISTOGRAM_SNAPSHOTS_H_
+