Headless: expose WebPreferences to embedder, add --hide-scrollbars.

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 13 matching lines @@
 class HeadlessResourceContext;
 class HeadlessWebContentsImpl;
 
 class HeadlessBrowserContextImpl : public HeadlessBrowserContext,
                                    public content::BrowserContext {
  public:
   ~HeadlessBrowserContextImpl() override;
 
   static HeadlessBrowserContextImpl* From(
       HeadlessBrowserContext* browser_context);
+  static HeadlessBrowserContextImpl* From(
+      content::BrowserContext* browser_context);
 
   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;
@@ skipping 53 matching lines @@
       web_contents_map_;
 
   std::string id_;
 
   DISALLOW_COPY_AND_ASSIGN(HeadlessBrowserContextImpl);
 };
 
 }  // namespace headless
 
 #endif  // HEADLESS_LIB_BROWSER_HEADLESS_BROWSER_CONTEXT_IMPL_H_