Consistently use LoFi for an entire page

content/common/navigation_params.h

 // Copyright 2014 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 CONTENT_COMMON_NAVIGATION_PARAMS_H_
 #define CONTENT_COMMON_NAVIGATION_PARAMS_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/common/frame_message_enums.h"
 #include "content/public/common/page_state.h"
 #include "content/public/common/referrer.h"
 #include "ui/base/page_transition_types.h"
 #include "url/gurl.h"
 
 namespace base {
 class RefCountedMemory;
 }
 
 namespace content {
 
+// The LoFi state which determines whether to add the Lo-Fi header.
+enum LoFiState {
+  // Let the browser process decide whether or not to request the Lo-Fi version.
+  LOFI_UNSPECIFIED = 0,
+
+  // Request a normal (non-Lo-Fi) version of the resource.
+  LOFI_OFF,
+
+  // Request a Lo-Fi version of the resource.
+  LOFI_ON,
+};
+
 // PlzNavigate
 // Helper function to determine if the navigation to |url| should make a request
 // to the network stack. A request should not be sent for data URLs, JavaScript
 // URLs or about:blank. In these cases, no request needs to be sent.
 bool ShouldMakeNetworkRequestForURL(const GURL& url);
 
 // The following structures hold parameters used during a navigation. In
 // particular they are used by FrameMsg_Navigate, FrameMsg_CommitNavigation and
 // FrameHostMsg_BeginNavigation.
 
@@ skipping 47 matching lines @@
   // The report type to be used when recording the metric using |ui_timestamp|.
   FrameMsg_UILoadMetricsReportType::Value report_type;
 
   // Base URL for use in Blink's SubstituteData.
   // Is only used with data: URLs.
   GURL base_url_for_data_url;
 
   // History URL for use in Blink's SubstituteData.
   // Is only used with data: URLs.
   GURL history_url_for_data_url;
+
+  // Whether or not to request a LoFi version of the document or let the browser
+  // decide.
+  LoFiState lofi_state;

[clamy, 2015/10/02 16:08:30]

Why are we adding this parameter to this struct? I cannot find a single instance
where it will be set to something else than LOFI_UNSPECIFIED. Also, if you add a
parameter to this struct, you should update its constructor.

[megjablon, 2015/10/02 17:47:39]

It's going to be used in a follow up cl that switches the snackbar that reloads
the page with images to using this mechanism. Added to the constructor.

 };
 
 // Provided by the renderer ----------------------------------------------------
 //
 // This struct holds parameters sent by the renderer to the browser. It is only
 // used in PlzNavigate (since in the current architecture, the renderer does not
 // inform the browser of navigations until they commit).
 
 // This struct is not used outside of the PlzNavigate project.
 // PlzNavigate: parameters needed to start a navigation on the IO thread,
@@ skipping 166 matching lines @@
   ~NavigationParams();
 
   CommonNavigationParams common_params;
   StartNavigationParams start_params;
   RequestNavigationParams request_params;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_NAVIGATION_PARAMS_H_