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

chrome/browser/loader/chrome_resource_dispatcher_host_delegate.cc

 // 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.
 
 #include "chrome/browser/loader/chrome_resource_dispatcher_host_delegate.h"
 
 #include <stdint.h>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 47 matching lines @@
 #include "content/public/browser/plugin_service_filter.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_context.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/service_worker_context.h"
 #include "content/public/browser/stream_info.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/previews_state.h"
 #include "content/public/common/resource_response.h"
 #include "extensions/features/features.h"
 #include "net/base/load_flags.h"
 #include "net/base/load_timing_info.h"
 #include "net/base/request_priority.h"
 #include "net/http/http_response_headers.h"
 #include "net/ssl/client_cert_store.h"
 #include "net/url_request/url_request.h"
 
 #if !defined(DISABLE_NACL)
@@ skipping 742 matching lines @@
       ResourceRequestInfo::ForRequest(url_request);
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&NotifyUIThreadOfRequestComplete,
                  info->GetWebContentsGetterForRequest(), url_request->url(),
                  info->GetResourceType(), url_request->was_cached(), net_error,
                  url_request->GetTotalReceivedBytes(),
                  base::TimeTicks::Now() - url_request->creation_time()));
 }
 
-bool ChromeResourceDispatcherHostDelegate::ShouldEnableLoFiMode(
+int ChromeResourceDispatcherHostDelegate::GetPreviewsState(
+    int previews_state,
     const net::URLRequest& url_request,
     content::ResourceContext* resource_context) {
-  ProfileIOData* io_data = ProfileIOData::FromResourceContext(resource_context);
-  data_reduction_proxy::DataReductionProxyIOData* data_reduction_proxy_io_data =
-      io_data->data_reduction_proxy_io_data();
+  if (previews_state & content::PREVIEWS_UNSPECIFIED) {

[RyanSturm, 2016/12/03 00:28:11]

Can you add a comment that previews_state is content::PREVIEWS_OFF when
reloading with LoFi disabled? When a new preview is added, I want it clear that
either they have to follow the reload with lofi off pattern for the preview, or
they should be aware that they might have define a preview state for LOFI_OFF
that their preview type could ignore here.

[megjablon, 2016/12/06 00:59:18]

Added the comment to resource_dispatcher_host_impl.cc since removing
PREVIEWS_UNSPECIFIED allowed me to go back to the original logic where
ChromeResourceDispatcherHostDelegate::GetPreviewsState isn't called unless the
state is "unspecified" (now 0).

+    ProfileIOData* io_data =
+        ProfileIOData::FromResourceContext(resource_context);
+    data_reduction_proxy::DataReductionProxyIOData*
+        data_reduction_proxy_io_data = io_data->data_reduction_proxy_io_data();
 
-  if (data_reduction_proxy_io_data)
-    return data_reduction_proxy_io_data->ShouldEnableLoFiMode(url_request);
-  return false;
+    if (data_reduction_proxy_io_data)
+      return data_reduction_proxy_io_data->ShouldEnableLoFiMode(url_request)
+                 ? content::SERVER_LOFI_ON
+                 : content::PREVIEWS_OFF;
+    return content::PREVIEWS_OFF;
+  }
+  return previews_state;
 }
 
 // static
 void ChromeResourceDispatcherHostDelegate::
     SetExternalProtocolHandlerDelegateForTesting(
     ExternalProtocolHandler::Delegate* delegate) {
   g_external_protocol_handler_delegate = delegate;
 }
 
 content::NavigationData*
@@ skipping 33 matching lines @@
           base::Bind(&ChromeResourceDispatcherHostDelegate::OnAbortedFrameLoad,
                     base::Unretained(this), url, request_loading_time));
       return;
   }
 
   std::string metric_name = (request_loading_time.InMilliseconds() < 100 ?
       "Net.ErrAborted.Fast" : "Net.ErrAborted.Slow");
   rappor::SampleDomainAndRegistryFromGURL(
       g_browser_process->rappor_service(), metric_name, url);
 }