Introduce the ANNOTATE_LEAKING_OBJECT_PTR annotation that can be used to mark

base/metrics/histogram.cc

 // Copyright (c) 2011 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.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 // See header file for details and examples.
 
 #include "base/metrics/histogram.h"
 
 #include <math.h>
 
 #include <algorithm>
 #include <string>
 
+#include "base/debug/leak_annotations.h"
 #include "base/logging.h"
 #include "base/pickle.h"
 #include "base/stringprintf.h"
 #include "base/synchronization/lock.h"
 
 namespace base {
 
 // Static table of checksums for all possible 8 bit bytes.
 const uint32 Histogram::kCrcTable[256] = {0x0, 0x77073096L, 0xee0e612cL,
 0x990951baL, 0x76dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0xedb8832L,
@@ skipping 996 matching lines @@
 
 // static
 bool StatisticsRecorder::IsActive() {
   if (lock_ == NULL)
     return false;
   base::AutoLock auto_lock(*lock_);
   return NULL != histograms_;
 }
 
 Histogram* StatisticsRecorder::RegisterOrDeleteDuplicate(Histogram* histogram) {
+  // As per crbug.com/79322 the histograms are intentionally leaked, so we need
+  // to annotate them. Because ANNOTATE_LEAKING_OBJECT_PTR may be used only once
+  // for an object, the duplicates should not be annotated.
+  // Callers are responsible for not calling RegisterOrDeleteDuplicate(ptr)
+  // twice if (lock_ == NULL) || (!histograms_).
   DCHECK(histogram->HasValidRangeChecksum());
-  if (lock_ == NULL)
+  if (lock_ == NULL) {
+    ANNOTATE_LEAKING_OBJECT_PTR(histogram);  // see crbug.com/79322
     return histogram;
+  }
   base::AutoLock auto_lock(*lock_);
-  if (!histograms_)
+  if (!histograms_) {
+    ANNOTATE_LEAKING_OBJECT_PTR(histogram);  // see crbug.com/79322
     return histogram;
+  }
   const std::string name = histogram->histogram_name();
   HistogramMap::iterator it = histograms_->find(name);
   // Avoid overwriting a previous registration.
   if (histograms_->end() == it) {
     (*histograms_)[name] = histogram;
+    ANNOTATE_LEAKING_OBJECT_PTR(histogram);  // see crbug.com/79322
   } else {
     delete histogram;  // We already have one by this name.
     histogram = it->second;
   }
   return histogram;
 }
 
 // static
 void StatisticsRecorder::WriteHTMLGraph(const std::string& query,
                                         std::string* output) {
@@ skipping 84 matching lines @@
 }
 
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;
 // static
 bool StatisticsRecorder::dump_on_exit_ = false;
 
 }  // namespace base