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

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 6c8ad23375dbcb01b52ab2c6176de2251c9c4413..f3b059c31b18f42fc608d5c4b09fccb2cd3f24b9 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -2326,7 +2326,7 @@ void RenderFrameImpl::OnReload(bool bypass_cache) {
 }
 
 void RenderFrameImpl::OnReloadLoFiImages() {
-  previews_state_ = PREVIEWS_NO_TRANSFORM;
+  previews_state_ = PREVIEWS_OFF;
   GetWebFrame()->ReloadLoFiImages();
 }
 
@@ -3740,11 +3740,18 @@ void RenderFrameImpl::DidCommitProvisionalLoad(
     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);
     }