Update CPAT protocol to send lite-page transform acceptance with ect

content/renderer/render_frame_impl.cc

 // Copyright 2013 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 "content/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 2308 matching lines @@
       source_frame, frame_->GetDocument(), std::move(channels));
   frame_->DispatchMessageEventWithOriginCheck(target_origin, msg_event);
 }
 
 void RenderFrameImpl::OnReload(bool bypass_cache) {
   frame_->Reload(bypass_cache ? WebFrameLoadType::kReloadBypassingCache
                               : WebFrameLoadType::kReload);
 }
 
 void RenderFrameImpl::OnReloadLoFiImages() {
-  previews_state_ = PREVIEWS_NO_TRANSFORM;
+  previews_state_ = PREVIEWS_OFF;
   GetWebFrame()->ReloadLoFiImages();
 }
 
 void RenderFrameImpl::OnTextSurroundingSelectionRequest(uint32_t max_length) {
   blink::WebSurroundingText surroundingText;
   surroundingText.InitializeFromCurrentSelection(frame_, max_length);
 
   if (surroundingText.IsNull()) {
     // |surroundingText| might not be correctly initialized, for example if
     // |frame_->selectionRange().isNull()|, in other words, if there was no
@@ skipping 1393 matching lines @@
   const WebURLResponse& web_url_response = frame_->DataSource()->GetResponse();
   WebURLResponseExtraDataImpl* extra_data =
       GetExtraDataFromResponse(web_url_response);
   // Only update the PreviewsState and effective connection type states for new
   // main frame documents. Subframes inherit from the main frame and should not
   // change at commit time.
   if (is_main_frame_ && !navigation_state->WasWithinSameDocument()) {
     previews_state_ =
         extra_data ? extra_data->previews_state() : PREVIEWS_OFF;
 
-    // Set lite pages off if a lite page was not loaded for the main frame.
-    if (web_url_response
-            .HttpHeaderField(
-                WebString::FromUTF8(kChromeProxyContentTransformHeader))
-            .Utf8() != kChromeProxyLitePageDirective) {
+    // Update previews state for subresources.
+    // TODO(dougarnett): Add support for alt-transforms directive to
+    // clear LoFi bit if not directed by server to use LoFi.

[bengr, 2017/05/01 16:53:14]

What is "LoFi bit"? 

Also, rename cpct as chrome _proxy_content_transform_value.

+    std::string cpct(web_url_response
+                         .HttpHeaderField(WebString::FromUTF8(
+                             kChromeProxyContentTransformHeader))
+                         .Utf8());
+    if (cpct == kChromeProxyLitePageDirective) {

[bengr, 2017/05/01 16:53:14]

Why do we have Chrome-specific code in content? Add TODO and file a bug.

+      // Received lite page so be sure LoFi is turned off for subresources.
+      previews_state_ &= ~(SERVER_LOFI_ON);
+    } else {
+      // Lite page not received so clear its bit for subresources, if set.
       previews_state_ &= ~(SERVER_LITE_PAGE_ON);
     }
 
     if (extra_data) {
       effective_connection_type_ =
           EffectiveConnectionTypeToWebEffectiveConnectionType(
               extra_data->effective_connection_type());
     }
   }
 
@@ skipping 3281 matching lines @@
       policy(info.default_policy),
       replaces_current_history_item(info.replaces_current_history_item),
       history_navigation_in_new_child_frame(
           info.is_history_navigation_in_new_child_frame),
       client_redirect(info.is_client_redirect),
       cache_disabled(info.is_cache_disabled),
       form(info.form),
       source_location(info.source_location) {}
 
 }  // namespace content