Add DebugInfo to DistilledPageProto.

components/dom_distiller/core/proto/distilled_page.proto

 // Copyright 2013 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.
 //
 // Distilled page content.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
@@ skipping 13 matching lines @@
 
     // The image data
     required bytes data = 2;
   }
 
   // The images referenced in the HTML.
   repeated Image image = 4;
 
   // Title for the current page.
   optional string title = 5;
-}
+
+  message DebugInfo {
+    // Contains the log from the JS distiller.
+    optional string log = 1;
+  }
+
+  // Debug information about this page.
+  optional DebugInfo debug_info = 6;
+}