Temporarily dump without crashing when setting an empty PageState.

content/browser/frame_host/frame_navigation_entry.cc

 // Copyright 2015 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 "content/browser/frame_host/frame_navigation_entry.h"
 
 #include <utility>
 
+#include "base/debug/dump_without_crashing.h"
 #include "content/common/page_state_serialization.h"
 #include "content/common/site_isolation_policy.h"
 
 namespace content {
 
 FrameNavigationEntry::FrameNavigationEntry()
     : item_sequence_number_(-1), document_sequence_number_(-1), post_id_(-1) {}
 
 FrameNavigationEntry::FrameNavigationEntry(
     const std::string& frame_unique_name,
@@ skipping 39 matching lines @@
     const PageState& page_state,
     const std::string& method,
     int64_t post_id) {
   frame_unique_name_ = frame_unique_name;
   item_sequence_number_ = item_sequence_number;
   document_sequence_number_ = document_sequence_number;
   site_instance_ = site_instance;
   source_site_instance_ = std::move(source_site_instance);
   url_ = url;
   referrer_ = referrer;
+  if (!page_state.IsValid()) {
+    // Temporarily generate a minidump to diagnose https://crbug.com/568703.
+    base::debug::DumpWithoutCrashing();
+    NOTREACHED() << "Shouldn't set an empty PageState.";
+  }
   page_state_ = page_state;
   method_ = method;
   post_id_ = post_id;
 }
 
 void FrameNavigationEntry::set_item_sequence_number(
     int64_t item_sequence_number) {
   // TODO(creis): Assert that this does not change after being assigned, once
   // location.replace is classified as NEW_PAGE rather than EXISTING_PAGE.
   // Same for document sequence number.  See https://crbug.com/596707.
@@ skipping 13 matching lines @@
 
   // Generate the body from the PageState.
   ExplodedPageState exploded_state;
   if (!DecodePageState(page_state_.ToEncodedData(), &exploded_state))
     return nullptr;
 
   return exploded_state.top.http_body.request_body;
 }
 
 }  // namespace content