Record call site history in LeakDetectorImpl

components/metrics/leak_detector/ranked_set.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 COMPONENTS_METRICS_LEAK_DETECTOR_RANKED_SET_H_
 #define COMPONENTS_METRICS_LEAK_DETECTOR_RANKED_SET_H_
 
 #include <stddef.h>
 
 #include <functional>  // for std::less
@@ skipping 54 matching lines @@
   //
   // Time complexity is O(log n).
   void Add(const ValueType& value, int count);
 
   // Helper functions to directly add a size or call stack to the RankedSet.
   void AddSize(size_t size, int count) { Add(ValueType(size), count); }
   void AddCallStack(const CallStack* call_stack, int count) {
     Add(ValueType(call_stack), count);
   }
 
+  // Helper functions to directly search for an element with |value| equal to a
+  // particular size or call stack. The time complexity is O(n) rather than the
+  // O(log n) typical of std::set. These should be called sparingly in
+  // performance-critical code.
+  const_iterator FindSize(size_t size) const { return Find(ValueType(size)); }
+  const_iterator FindCallStack(const CallStack* call_stack) const {
+    return Find(ValueType(call_stack));
+  }
+
  private:
+  // Returns an iterator to the element in |entries_| with value=|value|, or to
+  // entries_.end() if it was not found.
+  const_iterator Find(const ValueType& value) const;
+
   // Max and min counts. Returns 0 if the list is empty.
   int max_count() const {
     return entries_.empty() ? 0 : entries_.begin()->count;
   }
   int min_count() const {
     return entries_.empty() ? 0 : entries_.rbegin()->count;
   }
 
   // Max number of items that can be stored in the list.
   size_t max_size_;
 
   // Actual storage container for entries.
   EntrySet entries_;
 
   DISALLOW_COPY_AND_ASSIGN(RankedSet);
 };
 
 }  // namespace leak_detector
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_LEAK_DETECTOR_RANKED_SET_H_