Treat responses with legacy LoFi headers as LoFi images.

chrome/renderer/chrome_content_renderer_client.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/renderer/chrome_content_renderer_client.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 1366 matching lines @@
     RenderThread::Get()->GetConnector()->BindInterface(
         content::mojom::kBrowserServiceName, &rappor_recorder_);
   }
   rappor_recorder_->RecordRapporURL(metric, url);
 }
 
 void ChromeContentRendererClient::AddImageContextMenuProperties(
     const WebURLResponse& response,
     std::map<std::string, std::string>* properties) {
   DCHECK(properties);
-  WebString header_key(WebString::fromASCII(
+
+  WebString cpct_value = response.httpHeaderField(WebString::fromASCII(

[Lei Zhang, 2017/04/08 01:01:07]

Why do we have to go from const char* to WebString to std::string?

[sclittle, 2017/04/10 20:56:50]

We basically want to call:

drp::IsEmptyImagePreview(
    response.HttpHeaderField(drp::chrome_proxy_header()),
    response.HttpHeaderField(
        drp::chrome_proxy_content_transform_header()));

But since response.HttpHeaderField() both takes and returns WebStrings, we need
to convert the header names to WebStrings and the returned header values to
std::strings. Do you know of a more direct way to do this?

       data_reduction_proxy::chrome_proxy_content_transform_header()));
-  if (!response.httpHeaderField(header_key).isNull() &&
-      data_reduction_proxy::IsEmptyImagePreview(
-          response.httpHeaderField(header_key).utf8())) {
-    (*properties)[
-        data_reduction_proxy::chrome_proxy_content_transform_header()] =
+  WebString chrome_proxy_value = response.httpHeaderField(
+      WebString::fromASCII(data_reduction_proxy::chrome_proxy_header()));
+
+  if (data_reduction_proxy::IsEmptyImagePreview(cpct_value.utf8(),
+                                                chrome_proxy_value.utf8())) {
+    (*properties)
+        [data_reduction_proxy::chrome_proxy_content_transform_header()] =
             data_reduction_proxy::empty_image_directive();
   }
 }
 
 void ChromeContentRendererClient::RunScriptsAtDocumentStart(
     content::RenderFrame* render_frame) {
 #if BUILDFLAG(ENABLE_EXTENSIONS)
   ChromeExtensionsRendererClient::GetInstance()->RunScriptsAtDocumentStart(
       render_frame);
   // |render_frame| might be dead by now.
@@ skipping 115 matching lines @@
 
   RecordYouTubeRewriteUMA(result);
   return corrected_url.ReplaceComponents(r);
 }
 
 std::unique_ptr<base::TaskScheduler::InitParams>
 ChromeContentRendererClient::GetTaskSchedulerInitParams() {
   return task_scheduler_util::
       GetRendererTaskSchedulerInitParamsFromCommandLine();
 }