Rewrite base::JSONReader to be 35-40% faster, depending on the input string.

base/debug/trace_event_unittest.cc

 // Copyright (c) 2012 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 "base/debug/trace_event.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
@@ skipping 81 matching lines @@
 
 void TraceEventTestFixture::OnTraceDataCollected(
     const scoped_refptr<base::RefCountedString>& events_str) {
   AutoLock lock(lock_);
   json_output_.json_output.clear();
   trace_buffer_.Start();
   trace_buffer_.AddFragment(events_str->data());
   trace_buffer_.Finish();
 
   scoped_ptr<Value> root;
-  root.reset(base::JSONReader::Read(json_output_.json_output));
+  root.reset(base::JSONReader::Read(json_output_.json_output,
+                                    JSON_PARSE_RFC | JSON_DETACHABLE_CHILDREN));
 
   if (!root.get()) {
     LOG(ERROR) << json_output_.json_output;
   }
 
   ListValue* root_list = NULL;
   ASSERT_TRUE(root.get());
   ASSERT_TRUE(root->GetAsList(&root_list));
 
   // Move items into our aggregate collection
@@ skipping 1252 matching lines @@
   Clear();
 
   trace_buffer_.Start();
   trace_buffer_.AddFragment("bla1,bla2,bla3,bla4");
   trace_buffer_.Finish();
   EXPECT_STREQ(json_output_.json_output.c_str(), "[bla1,bla2,bla3,bla4]");
 }
 
 }  // namespace debug
 }  // namespace base