Adds a --deterministic-fetch flag to headless_shell

headless/lib/browser/headless_browser_context_impl.h

 // 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.
 
 #ifndef HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_CONTEXT_IMPL_H_
 #define HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_CONTEXT_IMPL_H_
 
 #include <memory>
 #include <string>
 #include <unordered_map>
@@ skipping 24 matching lines @@
   static std::unique_ptr<HeadlessBrowserContextImpl> Create(
       HeadlessBrowserContext::Builder* builder);
 
   // HeadlessBrowserContext implementation:
   HeadlessWebContents::Builder CreateWebContentsBuilder() override;
   std::vector<HeadlessWebContents*> GetAllWebContents() override;
   HeadlessWebContents* GetWebContentsForDevToolsAgentHostId(
       const std::string& devtools_agent_host_id) override;
   void Close() override;
   const std::string& Id() const override;
+  net::URLRequestContext* GetRequestContext() const override;
 
   // BrowserContext implementation:
   std::unique_ptr<content::ZoomLevelDelegate> CreateZoomLevelDelegate(
       const base::FilePath& partition_path) override;
   base::FilePath GetPath() const override;
   bool IsOffTheRecord() const override;
   content::ResourceContext* GetResourceContext() override;
   content::DownloadManagerDelegate* GetDownloadManagerDelegate() override;
   content::BrowserPluginGuestManager* GetGuestManager() override;
   storage::SpecialStoragePolicy* GetSpecialStoragePolicy() override;
@@ skipping 42 matching lines @@
       web_contents_map_;
 
   std::string id_;
 
   DISALLOW_COPY_AND_ASSIGN(HeadlessBrowserContextImpl);
 };
 
 }  // namespace headless
 
 #endif  // HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_CONTEXT_IMPL_H_