Adding MHTML support into Page Load Metrics

chrome/renderer/page_load_metrics/renderer_page_track_decider.cc

 // Copyright 2016 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/page_load_metrics/renderer_page_track_decider.h"
 
 #include <string>
 
 #include "chrome/renderer/searchbox/search_bouncer.h"
 #include "third_party/WebKit/public/platform/WebURLResponse.h"
@@ skipping 27 matching lines @@
   return data_source_->hasUnreachableURL();
 }
 
 int RendererPageTrackDecider::GetHttpStatusCode() {
   return data_source_->response().httpStatusCode();
 }
 
 bool RendererPageTrackDecider::IsHtmlOrXhtmlPage() {
   // Ignore non-HTML documents (e.g. SVG). Note that images are treated by
   // Blink as HTML documents, so to exclude images, we must perform
-  // additional mime type checking below.
+  // additional mime type checking below. MHTML is tracked as HTML in blink.
   if (!document_->isHTMLDocument() && !document_->isXHTMLDocument())
     return false;
 
   // Ignore non-HTML mime types (e.g. images).
   blink::WebString mime_type = data_source_->response().mimeType();
-  return mime_type == "text/html" || mime_type == "application/xhtml+xml";
+  return mime_type == "text/html" || mime_type == "application/xhtml+xml" ||
+         mime_type == "multipart/related";
 }
 
 }  // namespace page_load_metrics