Temporarily dump without crashing when setting an empty PageState.

content/browser/frame_host/navigation_entry_impl.cc

Index: content/browser/frame_host/navigation_entry_impl.cc
diff --git a/content/browser/frame_host/navigation_entry_impl.cc b/content/browser/frame_host/navigation_entry_impl.cc
index 9250e6811a31745d126c71bf78b67cae448382cd..c4c9f060d9022939433923f21a5d2f8fee7feb62 100644
--- a/content/browser/frame_host/navigation_entry_impl.cc
+++ b/content/browser/frame_host/navigation_entry_impl.cc
@@ -9,6 +9,7 @@
 #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"
@@ -52,6 +53,11 @@ void RecursivelyGenerateFrameEntries(const ExplodedFrameState& 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) {
@@ -771,6 +777,11 @@ void NavigationEntryImpl::AddOrUpdateFrameEntry(
       unique_name, item_sequence_number, document_sequence_number,
       site_instance, std::move(source_site_instance), url, referrer, method,
       post_id);
+  if (!page_state.IsValid()) {
+    // Temporarily generate a minidump to diagnose https://crbug.com/568703.
+    base::debug::DumpWithoutCrashing();
+    NOTREACHED() << "Shouldn't set an empty PageState.";
+  }
   frame_entry->set_page_state(page_state);
   parent_node->children.push_back(
       new NavigationEntryImpl::TreeNode(frame_entry));