QUIC - add instrumentation to HPACK.

net/spdy/hpack/hpack_header_table.cc

Index: net/spdy/hpack/hpack_header_table.cc
diff --git a/net/spdy/hpack/hpack_header_table.cc b/net/spdy/hpack/hpack_header_table.cc
index 01e96c09a0c71cb4240aba6da9dd66a9fd6282c7..a833def7358fbdd7b2d761da9b2e3949b6df31ec 100644
--- a/net/spdy/hpack/hpack_header_table.cc
+++ b/net/spdy/hpack/hpack_header_table.cc
@@ -52,7 +52,11 @@ const HpackEntry* HpackHeaderTable::GetByIndex(size_t index) {
   }
   index -= static_entries_.size();
   if (index < dynamic_entries_.size()) {
-    return &dynamic_entries_[index];
+    const HpackEntry* result = &dynamic_entries_[index];
+    if (debug_visitor_ != nullptr) {
+      debug_visitor_->OnUseEntry(*result);
+    }
+    return result;
   }
   return NULL;
 }
@@ -67,7 +71,11 @@ const HpackEntry* HpackHeaderTable::GetByName(StringPiece name) {
   {
     NameToEntryMap::const_iterator it = dynamic_name_index_.find(name);
     if (it != dynamic_name_index_.end()) {
-      return it->second;
+      const HpackEntry* result = it->second;
+      if (debug_visitor_ != nullptr) {
+        debug_visitor_->OnUseEntry(*result);
+      }
+      return result;
     }
   }
   return NULL;
@@ -85,7 +93,11 @@ const HpackEntry* HpackHeaderTable::GetByNameAndValue(StringPiece name,
   {
     UnorderedEntrySet::const_iterator it = dynamic_index_.find(&query);
     if (it != dynamic_index_.end()) {
-      return *it;
+      const HpackEntry* result = *it;
+      if (debug_visitor_ != nullptr) {
+        debug_visitor_->OnUseEntry(*result);
+      }
+      return result;
     }
   }
   return NULL;
@@ -220,6 +232,11 @@ const HpackEntry* HpackHeaderTable::TryAddEntry(StringPiece name,
 
   size_ += entry_size;
   ++total_insertions_;
+  if (debug_visitor_ != nullptr) {
+    // Call |debug_visitor_->OnNewEntry()| to get the current time.
+    HpackEntry& entry = dynamic_entries_.front();
+    entry.set_time_added(debug_visitor_->OnNewEntry(entry));
+  }
 
   return &dynamic_entries_.front();
 }