Change Lo-Fi bool to bitmask to support multiple Previews types

chrome/browser/loader/chrome_resource_dispatcher_host_delegate.h

 // Copyright (c) 2012 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 CHROME_BROWSER_LOADER_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 #define CHROME_BROWSER_LOADER_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/external_protocol/external_protocol_handler.h"
 #include "content/public/browser/resource_dispatcher_host_delegate.h"
+#include "content/public/common/previews_state.h"
 #include "extensions/features/features.h"
 
 class DownloadRequestLimiter;
 
 namespace content {
 class NavigationData;
 }
 
 namespace extensions {
 class UserScriptListener;
@@ skipping 48 matching lines @@
   void OnStreamCreated(net::URLRequest* request,
                        std::unique_ptr<content::StreamInfo> stream) override;
   void OnResponseStarted(net::URLRequest* request,
                          content::ResourceContext* resource_context,
                          content::ResourceResponse* response) override;
   void OnRequestRedirected(const GURL& redirect_url,
                            net::URLRequest* request,
                            content::ResourceContext* resource_context,
                            content::ResourceResponse* response) override;
   void RequestComplete(net::URLRequest* url_request) override;
-  bool ShouldEnableLoFiMode(
+  // Returns a bitmask of potentially several Previews optimizations.
+  content::PreviewsState GetPreviewsState(
       const net::URLRequest& url_request,
       content::ResourceContext* resource_context) override;
   content::NavigationData* GetNavigationData(
       net::URLRequest* request) const override;
   std::unique_ptr<net::ClientCertStore> CreateClientCertStore(
       content::ResourceContext* resource_context) override;
   void OnAbortedFrameLoad(const GURL& url,
                           base::TimeDelta request_loading_time) override;
 
   // Called on the UI thread. Allows switching out the
@@ skipping 21 matching lines @@
   scoped_refptr<safe_browsing::SafeBrowsingService> safe_browsing_;
 #if BUILDFLAG(ENABLE_EXTENSIONS)
   scoped_refptr<extensions::UserScriptListener> user_script_listener_;
   std::map<net::URLRequest*, StreamTargetInfo> stream_target_info_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ChromeResourceDispatcherHostDelegate);
 };
 
 #endif  // CHROME_BROWSER_LOADER_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_