Temporarily dump without crashing when setting an empty PageState.

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index c72e2eb067b922323fd1addb267a48e0677a3839..2b21fd9296ce3828ee0b2417a9174fc788e022e6 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -39,6 +39,7 @@
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/debug/dump_without_crashing.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram.h"
@@ -867,7 +868,11 @@ bool NavigationControllerImpl::RendererDidNavigate(
 
   // All committed entries should have nonempty content state so WebKit doesn't
   // get confused when we go back to them (see the function for details).
-  DCHECK(params.page_state.IsValid());
+  if (!params.page_state.IsValid()) {
+    // Temporarily generate a minidump to diagnose https://crbug.com/568703.
+    base::debug::DumpWithoutCrashing();
+    NOTREACHED() << "Shouldn't see an empty PageState at commit.";
+  }
   NavigationEntryImpl* active_entry = GetLastCommittedEntry();
   active_entry->SetTimestamp(timestamp);
   active_entry->SetHttpStatusCode(params.http_status_code);