DevTools: switch Timeline frontend into buffered mode and remove the corresponding experiment.

Source/core/inspector/InspectorTimelineAgent.cpp

 /*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
@@ skipping 809 matching lines @@
 void InspectorTimelineAgent::consoleTimeline(ExecutionContext* context, const String& title, ScriptState* scriptState)
 {
     if (!m_state->getBoolean(TimelineAgentState::enabled))
         return;
 
     String message = String::format("Timeline '%s' started.", title.utf8().data());
 
     mainFrame()->console().addMessage(JSMessageSource, DebugMessageLevel, message, String(), 0, 0, nullptr, scriptState);
     m_consoleTimelines.append(title);
     if (!isStarted()) {
+        m_state->setBoolean(TimelineAgentState::bufferEvents, true);
+        m_bufferedEvents = TypeBuilder::Array<TimelineEvent>::create();
+
         innerStart();
         bool fromConsole = true;
         m_frontend->started(&fromConsole);
     }
     appendRecord(TimelineRecordFactory::createTimeStampData(message), TimelineRecordType::TimeStamp, true, frameForExecutionContext(context));
 }
 
 void InspectorTimelineAgent::consoleTimelineEnd(ExecutionContext* context, const String& title, ScriptState* scriptState)
 {
     if (!m_state->getBoolean(TimelineAgentState::enabled))
@@ skipping 521 matching lines @@
     visitor->trace(m_timelineAgent);
 }
 
 void TimelineThreadState::trace(Visitor* visitor)
 {
     visitor->trace(recordStack);
 }
 
 } // namespace blink