Remove all blimp engine code

blimp/engine/app/blimp_system_url_request_context_getter.cc

-// Copyright 2016 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 "blimp/engine/app/blimp_system_url_request_context_getter.h"
-
-#include <utility>
-#include <vector>
-
-#include "base/logging.h"
-#include "base/single_thread_task_runner.h"
-#include "blimp/engine/common/blimp_user_agent.h"
-#include "content/public/browser/browser_thread.h"
-#include "net/proxy/proxy_service.h"
-#include "net/url_request/url_request_context.h"
-#include "net/url_request/url_request_context_builder.h"
-
-namespace blimp {
-namespace engine {
-
-BlimpSystemURLRequestContextGetter::BlimpSystemURLRequestContextGetter() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-}
-
-BlimpSystemURLRequestContextGetter::~BlimpSystemURLRequestContextGetter() {}
-
-net::URLRequestContext*
-BlimpSystemURLRequestContextGetter::GetURLRequestContext() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-  if (!url_request_context_) {
-    // Use default values
-    net::URLRequestContextBuilder builder;
-
-    // TODO(jessicag): See if proxy_service setup should be harmonized with
-    // user request context getter. http://crbug/609981
-    builder.set_proxy_service(net::ProxyService::CreateDirect());
-    builder.set_user_agent(GetBlimpEngineUserAgent());
-    url_request_context_ = builder.Build();
-  }
-  return url_request_context_.get();
-}
-
-scoped_refptr<base::SingleThreadTaskRunner>
-BlimpSystemURLRequestContextGetter::GetNetworkTaskRunner() const {
-  return content::BrowserThread::GetTaskRunnerForThread(
-      content::BrowserThread::IO);
-}
-
-}  // namespace engine
-}  // namespace blimp