Classify navigations without page id in parallel to the existing classifier.

content/public/common/frame_navigate_params.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_COMMON_FRAME_NAVIGATE_PARAMS_H_
 #define CONTENT_PUBLIC_COMMON_FRAME_NAVIGATE_PARAMS_H_
 
 #include <string>
 #include <vector>
 
 #include "content/common/content_export.h"
 #include "content/public/common/referrer.h"
 #include "net/base/host_port_pair.h"
 #include "ui/base/page_transition_types.h"
 #include "url/gurl.h"
 
 namespace content {
 
 // Struct used by WebContentsObserver.
 struct CONTENT_EXPORT FrameNavigateParams {
   FrameNavigateParams();
   ~FrameNavigateParams();
 
   // Page ID of this navigation. The renderer creates a new unique page ID
   // anytime a new session history entry is created. This means you'll get new
   // page IDs for user actions, and the old page IDs will be reloaded when
   // iframes are loaded automatically.
   int32 page_id;

[Charlie Reis, 2015/03/12 18:28:17]

Same here.

 
+  // The unique ID of the NavigationEntry for browser-initiated navigations.
+  // This value was given to the render process in the HistoryNavigationParams
+  // and is being returned by the renderer without it having any idea what it
+  // means.
+  int nav_entry_id;
+
   // URL of the page being loaded.
   GURL url;
 
   // The base URL for the page's document when the frame was committed. Empty if
   // similar to 'url' above. Note that any base element in the page has not been
   // parsed yet and is therefore not reflected.
   // This is of interest when a MHTML file is loaded, as the base URL has been
   // set to original URL of the site the MHTML represents.
   GURL base_url;
 
@@ skipping 21 matching lines @@
   // Contents MIME type of main frame.
   std::string contents_mime_type;
 
   // Remote address of the socket which fetched this resource.
   net::HostPortPair socket_address;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_FRAME_NAVIGATE_PARAMS_H_