[headless] Remove default browser context.

headless/lib/browser/headless_browser_main_parts.cc

 // Copyright 2015 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 "headless/lib/browser/headless_browser_main_parts.h"
 
 #include "components/devtools_http_handler/devtools_http_handler.h"
+#include "content/public/browser/browser_thread.h"
 #include "headless/lib/browser/headless_browser_context_impl.h"
 #include "headless/lib/browser/headless_browser_impl.h"
 #include "headless/lib/browser/headless_devtools.h"
+#include "headless/lib/browser/headless_devtools_manager_delegate.h"
 #include "headless/lib/browser/headless_screen.h"
 #include "ui/aura/env.h"
 #include "ui/display/screen.h"
 
 namespace headless {
 
 namespace {
 
 void PlatformInitialize() {
   HeadlessScreen* screen = HeadlessScreen::Create(gfx::Size());
   display::Screen::SetScreenInstance(screen);
 }
 
 void PlatformExit() {
 }
 
 }  // namespace
 
 HeadlessBrowserMainParts::HeadlessBrowserMainParts(HeadlessBrowserImpl* browser)
     : browser_(browser) {}
 
 HeadlessBrowserMainParts::~HeadlessBrowserMainParts() {}
 
 void HeadlessBrowserMainParts::PreMainMessageLoopRun() {
-  browser_context_.reset(new HeadlessBrowserContextImpl(ProtocolHandlerMap(),
-                                                        browser_->options()));
   if (browser_->options()->devtools_endpoint.address().IsValid()) {
     devtools_http_handler_ =
-        CreateLocalDevToolsHttpHandler(browser_context_.get());
+        CreateLocalDevToolsHttpHandler(browser_->options());
   }
   PlatformInitialize();
 }
 
 void HeadlessBrowserMainParts::PostMainMessageLoopRun() {
-  browser_context_.reset();
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
   devtools_http_handler_.reset();
+
   PlatformExit();
 }
 
-HeadlessBrowserContextImpl* HeadlessBrowserMainParts::default_browser_context()
-    const {
-  return browser_context_.get();
-}
-
 }  // namespace headless