Leak reports collect information about the last uptrend

components/metrics/leak_detector/call_stack_table.h

Index: components/metrics/leak_detector/call_stack_table.h
diff --git a/components/metrics/leak_detector/call_stack_table.h b/components/metrics/leak_detector/call_stack_table.h
index 77a4b2a3ed717d882f44fb2403eb93b73315348d..e8a4fb2d92a7ce907bdba7a0c72960e7ed60aa6e 100644
--- a/components/metrics/leak_detector/call_stack_table.h
+++ b/components/metrics/leak_detector/call_stack_table.h
@@ -48,6 +48,14 @@ class CallStackTable {
   // must already be initialized with that number.
   void GetTopCallStacks(RankedSet* top_entries) const;
 
+  // Updates fields in CallStackCountInfo for every stored call stack.

[Simon Que, 2016/10/11 01:11:05]

Explain the behavior in more detail. Mention e.g. when this function should be
called.

[mwlodar, 2016/10/11 07:13:23]

Done.

+  void UpdateLastDropInfo(size_t timestamp);
+
+  // Retrieves the number of timestamps and the count growth since the last

[Simon Que, 2016/10/11 01:11:05]

"number of timestamps" isn't quite right... did you mean "change in timestamp"?

[mwlodar, 2016/10/11 07:13:24]

Done.

+  // observed drop in the number for allocations for the given call stack.
+  void GetLastUptrendInfo(const CallStack* call_stack, size_t timestamp,
+                       size_t *timestamp_delta, uint32_t *count_delta) const;

[Simon Que, 2016/10/11 01:11:05]

Nit: alignment

[mwlodar, 2016/10/11 07:13:23]

Done.

+
   const LeakAnalyzer& leak_analyzer() const { return leak_analyzer_; }
 
   size_t size() const { return entry_map_.size(); }
@@ -57,6 +65,11 @@ class CallStackTable {
   uint32_t num_frees() const { return num_frees_; }
 
  private:
+  struct CallStackCountInfo {
+    uint32_t count, previous_count, last_drop_count;
+    size_t last_drop_timestamp;
+  };
+
   // Total number of allocs and frees in this table.
   uint32_t num_allocs_;
   uint32_t num_frees_;
@@ -70,7 +83,7 @@ class CallStackTable {
   // Stores a mapping of each call stack to the number of recorded allocations
   // made from that call site.
   base::hash_map<const CallStack*,
-                 uint32_t,
+                 CallStackCountInfo,
                  StoredHash,
                  std::equal_to<const CallStack*>,
                  TableEntryAllocator> entry_map_;