Leak reports collect information about the memory usage

chrome/browser/metrics/metrics_memory_details.h

 // Copyright 2015 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_BROWSER_METRICS_METRICS_MEMORY_DETAILS_H_
 #define CHROME_BROWSER_METRICS_METRICS_MEMORY_DETAILS_H_
 
 #include <map>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/browser/memory_details.h"
 
 // MemoryGrowthTracker tracks latest metrics about record time and memory usage
 // at that time per process.
 class MemoryGrowthTracker {
  public:
   MemoryGrowthTracker();
-  ~MemoryGrowthTracker();
+  virtual ~MemoryGrowthTracker();
 
   // If 30 minutes have passed since last UMA record, UpdateSample() computes
   // a difference between current memory usage |sample| of process |pid| and
   // stored memory usage at the time of last UMA record. Then, it updates the
   // stored memory usage to |sample|, stores the difference in |diff| and
   // returns true.
   // If no memory usage of |pid| has not been recorded so far or 30 minutes
   // have not passed since last record, it just returns false.
   // |sample| is memory usage in kB.
-  bool UpdateSample(base::ProcessId pid, int sample, int* diff);
+  virtual bool UpdateSample(base::ProcessId pid, int sample, int* diff);
 
  private:
   // Latest metrics about record time and memory usage at that time per process.
   // The second values of |memory_sizes_| are in kB.
   std::map<base::ProcessId, base::TimeTicks> times_;
   std::map<base::ProcessId, int> memory_sizes_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryGrowthTracker);
 };
 
 // Handles asynchronous fetching of memory details and logging histograms about
 // memory use of various processes.
 // Will run the provided callback when finished.
 class MetricsMemoryDetails : public MemoryDetails {
  public:
   MetricsMemoryDetails(const base::Closure& callback,
                        MemoryGrowthTracker* memory_growth_tracker);
 
+  void set_generate_histograms(bool generate_histograms) {
+    generate_histograms_ = generate_histograms;
+  }
+
  protected:
   ~MetricsMemoryDetails() override;
 
   // MemoryDetails:
   void OnDetailsAvailable() override;
 
  private:
   // Updates the global histograms for tracking memory usage.
   void UpdateHistograms();
 
 #if defined(OS_CHROMEOS)
   void UpdateSwapHistograms();
 #endif
 
+  // Notifies |memory_growth_tracker_| about the memory usage.
+  // Update histograms on memory growth or shrink in renderer processes.
+  void AnalyzeMemoryGrowth();
+
   base::Closure callback_;
 
   // A pointer to MemoryGrowthTracker which is contained in a longer-lived
   // owner of MetricsMemoryDetails, for example, ChromeMetricsServiceClient.
   // If it is null, nothing is tracked.
   MemoryGrowthTracker* memory_growth_tracker_;
 
+  // A flag indicating if histogram data should be generated. True on default.
+  // If false, then only MemoryGrowthTracker gets notified about memory usage.
+  bool generate_histograms_;
+
   DISALLOW_COPY_AND_ASSIGN(MetricsMemoryDetails);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_MEMORY_DETAILS_H_