[counters] Use separate counters for background parsing

src/parsing/preparser.cc

 // Copyright 2011 the V8 project 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 <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 164 matching lines @@
 PreParser::Expression PreParser::ParseFunctionLiteral(
     Identifier function_name, Scanner::Location function_name_location,
     FunctionNameValidity function_name_validity, FunctionKind kind,
     int function_token_pos, FunctionLiteral::FunctionType function_type,
     LanguageMode language_mode, bool* ok) {
   // Function ::
   //   '(' FormalParameterList? ')' '{' FunctionBody '}'
   RuntimeCallTimerScope runtime_timer(
       runtime_call_stats_,
       track_unresolved_variables_
-          ? &RuntimeCallStats::PreParseWithVariableResolution
-          : &RuntimeCallStats::PreParseNoVariableResolution);
+          ? parsing_on_main_thread_
+                ? &RuntimeCallStats::PreParseWithVariableResolution
+                : &RuntimeCallStats::PreParseBackgroundWithVariableResolution
+          : parsing_on_main_thread_
+                ? &RuntimeCallStats::PreParseNoVariableResolution
+                : &RuntimeCallStats::PreParseBackgroundNoVariableResolution);
 
   // Parse function body.
   PreParserStatementList body;
   DeclarationScope* function_scope = NewFunctionScope(kind);
   function_scope->SetLanguageMode(language_mode);
   FunctionState function_state(&function_state_, &scope_state_, function_scope);
   DuplicateFinder duplicate_finder(scanner()->unicode_cache());
   ExpressionClassifier formals_classifier(this, &duplicate_finder);
 
   Expect(Token::LPAREN, CHECK_OK);
@@ skipping 97 matching lines @@
     }
   }
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_CUSTOM
 
 
 }  // namespace internal
 }  // namespace v8