Temporarily dump without crashing when setting an empty PageState.

content/browser/frame_host/navigation_entry_impl.cc

 // 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.
 
 #include "content/browser/frame_host/navigation_entry_impl.h"
 
 #include <stddef.h>
 
 #include <queue>
 #include <utility>
 
+#include "base/debug/dump_without_crashing.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "components/url_formatter/url_formatter.h"
 #include "content/common/content_constants_internal.h"
 #include "content/common/navigation_params.h"
 #include "content/common/page_state_serialization.h"
 #include "content/common/resource_request_body_impl.h"
@@ skipping 23 matching lines @@
       state.document_sequence_number, nullptr, nullptr,
       GURL(state.url_string.string()),
       Referrer(GURL(state.referrer.string()), state.referrer_policy), "GET",
       -1);
 
   // Set a single-frame PageState on the entry.
   ExplodedPageState page_state;
   page_state.top = state;
   std::string data;
   EncodePageState(page_state, &data);
+  if (data.empty()) {
+    // Temporarily generate a minidump to diagnose https://crbug.com/568703.
+    base::debug::DumpWithoutCrashing();
+    NOTREACHED() << "Shouldn't generate an empty PageState.";
+  }
   node->frame_entry->set_page_state(PageState::CreateFromEncodedData(data));
 
   for (const ExplodedFrameState& child_state : state.children) {
     NavigationEntryImpl::TreeNode* child_node =
         new NavigationEntryImpl::TreeNode(nullptr);
     node->children.push_back(child_node);
     RecursivelyGenerateFrameEntries(child_state, child_node);
   }
 }
 
@@ skipping 673 matching lines @@
   // commits.  Find it first.
   DCHECK(frame_tree_node->parent());
   NavigationEntryImpl::TreeNode* parent_node =
       FindFrameEntry(frame_tree_node->parent());
   if (!parent_node) {
     // The renderer should not send a commit for a subframe before its parent.
     // TODO(creis): Kill the renderer if we get here.
     return;
   }
 
+  // We should only have an empty PageState if the navigation is new, and thus
+  // page ID is -1.
+  if (!page_state.IsValid() && GetPageID() != -1) {
+    // Temporarily generate a minidump to diagnose https://crbug.com/568703.
+    base::debug::DumpWithoutCrashing();
+    NOTREACHED() << "Shouldn't set an empty PageState.";
+  }
+
   // Now check whether we have a TreeNode for the node itself.
   const std::string& unique_name = frame_tree_node->unique_name();
   for (TreeNode* child : parent_node->children) {
     if (child->frame_entry->frame_unique_name() == unique_name) {
       // If the document of the FrameNavigationEntry is changing, we must clear
       // any child FrameNavigationEntries.
       if (child->frame_entry->document_sequence_number() !=
           document_sequence_number)
         child->children.clear();
 
@@ skipping 53 matching lines @@
       return node;
 
     // Enqueue any children and keep looking.
     for (auto* child : node->children)
       work_queue.push(child);
   }
   return nullptr;
 }
 
 }  // namespace content