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

components/data_reduction_proxy/content/browser/content_lofi_decider.cc

 // 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.
 
 #include "components/data_reduction_proxy/content/browser/content_lofi_decider.h"
 
 #include <string>
 
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ skipping 25 matching lines @@
   // Return if the user is using Lo-Fi and not part of the "Control" group.
   if (request_info) {
     return (request_info->GetPreviewsState() & content::SERVER_LOFI_ON) &&
            lofi_enabled_via_flag_or_field_trial;
   }
   return false;
 }
 
 void ContentLoFiDecider::MaybeSetAcceptTransformHeader(
     const net::URLRequest& request,
-    bool are_previews_disabled,
     net::HttpRequestHeaders* headers) const {
   const content::ResourceRequestInfo* request_info =
       content::ResourceRequestInfo::ForRequest(&request);
 
   if (!request_info)
     return;
 
   // Previews only operate on HTTP.
   if (!request.url().SchemeIs("http"))
     return;
 
   // Chrome-Proxy-Accept-Transform takes at most one token.
   if (headers->HasHeader(chrome_proxy_accept_transform_header()))
     return;
 
   content::ResourceType resource_type = request_info->GetResourceType();
 
   if (resource_type == content::RESOURCE_TYPE_MEDIA) {
     headers->SetHeader(chrome_proxy_accept_transform_header(),
                        compressed_video_directive());
     return;
   }
 
-  // The Lo-Fi and Lite Page directives should not be added for users in the
-  // Lo-Fi field trial "Control" group.
-  bool lofi_enabled_via_flags_or_field_trial =
-      params::IsLoFiOnViaFlags() || params::IsIncludedInLoFiEnabledFieldTrial();
-
-  bool lite_page_enabled_via_flags_or_field_trial =
-      (params::IsLoFiOnViaFlags() && params::AreLitePagesEnabledViaFlags()) ||
-      params::IsIncludedInLitePageFieldTrial();
-
-  // User does not have previews enabled.
-  if (!lofi_enabled_via_flags_or_field_trial &&
-      !lite_page_enabled_via_flags_or_field_trial) {
-    return;
-  }
-
-  // Previews has been disabled.
-  if (are_previews_disabled)
+  // Do not add the Chrome-Proxy-Accept-Transform header if the request
+  // has previews turned off.
+  content::PreviewsState previews_state = request_info->GetPreviewsState();
+  if (previews_state & content::PREVIEWS_OFF)
     return;
 
+  // TODO(dougarnett): Remove once blink uses Off instead of NoTransform.
   // Do not add the Chrome-Proxy-Accept-Transform header when the page load
   // explicitly forbids previews transformations.
-  if (request_info->GetPreviewsState() & content::PREVIEWS_NO_TRANSFORM)
+  if (previews_state & content::PREVIEWS_NO_TRANSFORM)
     return;
 
   // Lo-Fi is not allowed on the main frame, stylesheet, script, font resource,
   // media, service worker, or CSP report.
   bool resource_type_supports_empty_image =

[bengr, 2017/05/01 16:53:13]

Hmm. I don't see this being used anymore, but it should be, right?

       !(resource_type == content::RESOURCE_TYPE_MAIN_FRAME ||
         resource_type == content::RESOURCE_TYPE_STYLESHEET ||
         resource_type == content::RESOURCE_TYPE_SCRIPT ||
         resource_type == content::RESOURCE_TYPE_FONT_RESOURCE ||
         resource_type == content::RESOURCE_TYPE_MEDIA ||
         resource_type == content::RESOURCE_TYPE_CSP_REPORT);
 
   // If the Lite Page field trial or flag is enabled, only add the "lite-page"
   // directive on main frame requests. Only add "empty-image" directives to
   // other requests when Lite Page previews are not enabled after the main
-  // frame. Add the "if-heavy" qualifier to allow the server to provide a
-  // preview when the page is data heavy on if a preview was not otherwise
-  // triggered.
+  // frame.
   std::string accept_transform_value;
-  if (lite_page_enabled_via_flags_or_field_trial &&
+  if ((previews_state & content::SERVER_LITE_PAGE_ON) &&
       resource_type == content::RESOURCE_TYPE_MAIN_FRAME) {
     accept_transform_value = lite_page_directive();
-
-    // Since a Lite Page was not triggered client side, ask the server to
-    // provide a Lite Page only if the page is otherwise data-heavy.
-    if (!(request_info->GetPreviewsState() & content::SERVER_LITE_PAGE_ON))
-      accept_transform_value += base::StringPrintf(";%s", if_heavy_qualifier());
-  } else if (lofi_enabled_via_flags_or_field_trial &&
-             // Only use Lo-Fi if Lite Pages aren't enabled or fallback from
-             // Lite Pages to Lo-Fi is enabled.
-             (!lite_page_enabled_via_flags_or_field_trial ||
-              params::IsLitePageFallbackEnabled()) &&
-             resource_type_supports_empty_image &&
-             !(request_info->GetPreviewsState() &
-               content::SERVER_LITE_PAGE_ON)) {
+  } else if ((previews_state & content::SERVER_LOFI_ON) &&
+             resource_type_supports_empty_image) {
     accept_transform_value = empty_image_directive();
-
-    // Since Lo-Fi was not triggered client side, ask the server to provide
-    // Lo-Fi only if the page is otherwise data-heavy.
-    if (!(request_info->GetPreviewsState() & content::SERVER_LOFI_ON))
-      accept_transform_value += base::StringPrintf(";%s", if_heavy_qualifier());
   }
   if (accept_transform_value.empty())
     return;
 
   headers->SetHeader(chrome_proxy_accept_transform_header(),
                      accept_transform_value);
 }
 
 bool ContentLoFiDecider::IsSlowPagePreviewRequested(
     const net::HttpRequestHeaders& headers) const {
@@ skipping 30 matching lines @@
   std::string transform_type;
   base::TrimWhitespaceASCII(tokens[0], base::TRIM_ALL, &transform_type);
   return transform_type == lite_page_directive();
 }
 
 void ContentLoFiDecider::RemoveAcceptTransformHeader(
     net::HttpRequestHeaders* headers) const {
   headers->RemoveHeader(chrome_proxy_accept_transform_header());
 }
 
-void ContentLoFiDecider::MaybeSetIgnorePreviewsBlacklistDirective(
+void ContentLoFiDecider::MaybeSetForceLitePageDirective(
     net::HttpRequestHeaders* headers) const {
+  // Ensure lite page is requested in headers and enabled via flag.

[bengr, 2017/05/01 16:53:13]

This is very confusing. If lite pages are requested in command line flags and
the request already has c-p-a-t: lite-page, it seems we add lite-page to the
list of directives in c-p-a-t? Am I reading this wrong?

   if (!headers || !params::AreLitePagesEnabledViaFlags() ||
       !IsLitePagePreviewRequested(*headers)) {
     return;
   }
+
   std::string chrome_proxy_header_value;
   headers->GetHeader(chrome_proxy_header(), &chrome_proxy_header_value);
   headers->RemoveHeader(chrome_proxy_header());
   if (!chrome_proxy_header_value.empty())
     chrome_proxy_header_value += ", ";
-  chrome_proxy_header_value +=
-      chrome_proxy_lite_page_ignore_blacklist_directive();
+  chrome_proxy_header_value += chrome_proxy_force_lite_page_directive();
   headers->SetHeader(chrome_proxy_header(), chrome_proxy_header_value);
 }
 
-bool ContentLoFiDecider::ShouldRecordLoFiUMA(
+bool ContentLoFiDecider::ShouldRecordPreviewsUMA(
     const net::URLRequest& request) const {
   const content::ResourceRequestInfo* request_info =
       content::ResourceRequestInfo::ForRequest(&request);
 
   // User is not using Lo-Fi.
   if (!request_info ||
       !(request_info->GetPreviewsState() & content::SERVER_LOFI_ON ||
         request_info->GetPreviewsState() & content::SERVER_LITE_PAGE_ON)) {
     return false;
   }
 
   return params::IsIncludedInLoFiEnabledFieldTrial() ||
          params::IsIncludedInLoFiControlFieldTrial();
 }
 
 }  // namespace data_reduction_proxy