Record call site history in LeakDetectorImpl

components/metrics/leak_detector/ranked_set.cc

 // 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.
 
 #include "components/metrics/leak_detector/ranked_set.h"
 
 #include <algorithm>
 
 namespace metrics {
 namespace leak_detector {
@@ skipping 30 matching lines @@
   new_entry.count = count;
   entries_.insert(new_entry);
 
   // Limit the container size if it exceeds the maximum allowed size, by
   // deleting the last element. This should only iterate once because the size
   // can only have increased by 1, but use a while loop just to be safe.
   while (entries_.size() > max_size_)
     entries_.erase(--entries_.end());
 }
 
+RankedSet::const_iterator RankedSet::Find(const ValueType& value) const {
+  // The entries are stored sorted by |count|, but this function looks for an
+  // entry with a particular |value| field. Thus, std::set::find() will not
+  // work. Nor would std::find(), which matches by both |count| and |value| --
+  // the count is unknown to the caller of this function.
+  //
+  // The most straightforward way is to iterate through the set until a matching
+  // value is found.
+  for (const_iterator iter = begin(); iter != end(); ++iter) {
+    if (iter->value == value)
+      return iter;
+  }
+  return end();
+}
+
 }  // namespace leak_detector
 }  // namespace metrics